Tasks Details
medium
1.
Flags
Find the maximum number of flags that can be set on mountain peaks.
Task Score
100%
Correctness
100%
Performance
100%
A non-empty array A consisting of N integers is given.
A peak is an array element which is larger than its neighbours. More precisely, it is an index P such that 0 < P < N − 1 and A[P − 1] < A[P] > A[P + 1].
For example, the following array A:
A[0] = 1 A[1] = 5 A[2] = 3 A[3] = 4 A[4] = 3 A[5] = 4 A[6] = 1 A[7] = 2 A[8] = 3 A[9] = 4 A[10] = 6 A[11] = 2has exactly four peaks: elements 1, 3, 5 and 10.
You are going on a trip to a range of mountains whose relative heights are represented by array A, as shown in a figure below. You have to choose how many flags you should take with you. The goal is to set the maximum number of flags on the peaks, according to certain rules.
Flags can only be set on peaks. What's more, if you take K flags, then the distance between any two flags should be greater than or equal to K. The distance between indices P and Q is the absolute value |P − Q|.
For example, given the mountain range represented by array A, above, with N = 12, if you take:
- two flags, you can set them on peaks 1 and 5;
- three flags, you can set them on peaks 1, 5 and 10;
- four flags, you can set only three flags, on peaks 1, 5 and 10.
You can therefore set a maximum of three flags in this case.
Write a function:
class Solution { public int solution(int[] A); }
that, given a non-empty array A of N integers, returns the maximum number of flags that can be set on the peaks of the array.
For example, the following array A:
A[0] = 1 A[1] = 5 A[2] = 3 A[3] = 4 A[4] = 3 A[5] = 4 A[6] = 1 A[7] = 2 A[8] = 3 A[9] = 4 A[10] = 6 A[11] = 2the function should return 3, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..400,000];
- each element of array A is an integer within the range [0..1,000,000,000].
Copyright 2009–2024 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 61 minutes
Notes
not defined yet
Task timeline
Code: 06:08:03 UTC,
java,
autosave
Code: 06:58:52 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > ])
}
}
}
Code: 06:59:08 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
}
}
Code: 06:59:24 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
}
}
Code: 06:59:55 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeask = new int[A.]
}
}
Code: 07:00:06 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeask = new int[A.length];
}
}
Code: 07:00:36 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeask = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
n
}
}
}
}
Code: 07:00:54 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeask = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
}
}
Code: 07:01:10 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
}
}
Code: 07:01:32 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
}
Code: 07:02:24 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
}
Code: 07:02:35 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
}
Code: 07:02:59 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
}
}
Code: 07:03:13 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
}
Code: 07:03:24 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
}
Code: 07:03:37 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks() {
}
}
Code: 07:03:53 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
}
}
Code: 07:04:19 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
}
Code: 07:04:19 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = new int[A.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return result = 0;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
}
Code: 07:04:48 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (checkToSetFlags(nextPeak))
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
}
Code: 07:05:05 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (checkToSetFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean checkToSetFlags()
}
Code: 07:05:43 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags()
}
Code: 07:05:43 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (checkToSetFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckSetFlags()
}
Code: 07:05:53 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum)
}
Code: 07:06:23 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || le)
}
}
}
Code: 07:06:53 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Code: 07:07:21 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Code: 07:07:32 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate peak's coutn
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Code: 07:07:51 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Code: 07:07:52 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis
Compile error
Solution.java:25: error: incompatible types: boolean cannot be converted to int
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
^
Solution.java:25: error: incompatible types: int cannot be converted to boolean
if (A[idx > A[idx - 1] && A[idx] > A[idx + 1]]) {
^
Solution.java:44: error: cannot find symbol
for (int idx = 0; idx < flageNum; idx++) {
^
symbol: variable flageNum
location: class Solution
3 errors
Code: 07:08:03 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis
Compile error
Solution.java:25: error: ')' expected
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]]) {
^
Solution.java:25: error: ';' expected
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]]) {
^
2 errors
Code: 07:08:07 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flageNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis
Compile error
Solution.java:44: error: cannot find symbol
for (int idx = 0; idx < flageNum; idx++) {
^
symbol: variable flageNum
location: class Solution
1 error
Code: 07:08:21 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flagNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis
Code: 07:08:28 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flagNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis
Code: 07:08:32 UTC,
java,
final,
score:
100
// you can also use imports, for example:
// import java.util.*;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int[] A) {
int result = 0;
// Check to peak's index.
boolean[] peaks = getPeaks(A);
// Check to next peak's index.
int[] nextPeaks = getNextPeaks(peaks);
// Calculate count of peaks.
for (int idx = 1; (idx - 1) * idx < A.length; idx++) {
if (isCheckFlags(nextPeaks, idx)) {
result = Math.max(result, idx);
}
}
return result;
}
private boolean[] getPeaks(int[] A) {
boolean[] peaks = new boolean[A.length];
for (int idx = 1; idx < A.length - 1; idx++) {
if (A[idx] > A[idx - 1] && A[idx] > A[idx + 1]) {
peaks[idx] = true;
}
}
return peaks;
}
private int[] getNextPeaks(boolean[] peaks) {
int[] nextPeaks = new int[peaks.length];
int nextPeak = -1;
for (int idx = nextPeaks.length - 1; idx >= 0; idx--) {
if (peaks[idx]) {
nextPeak = idx;
}
nextPeaks[idx] = nextPeak;
}
return nextPeaks;
}
private boolean isCheckFlags(int[] nextPeaks, int flagNum) {
int index = 0;
for (int idx = 0; idx < flagNum; idx++) {
if (index >= nextPeaks.length || nextPeaks[index] < 0) {
return false;
}
index = nextPeaks[index] + flagNum;
}
return true;
}
}
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N)
expand all
Correctness tests
1.
0.012 s
OK
2.
0.008 s
OK
3.
0.012 s
OK
1.
0.008 s
OK
2.
0.012 s
OK
3.
0.012 s
OK
4.
0.012 s
OK
5.
0.012 s
OK
1.
0.008 s
OK
2.
0.008 s
OK
1.
0.012 s
OK
1.
0.012 s
OK
1.
0.012 s
OK
1.
0.044 s
OK
2.
0.024 s
OK
1.
0.008 s
OK
2.
0.024 s
OK
expand all
Performance tests
1.
0.348 s
OK
2.
0.164 s
OK
1.
0.280 s
OK
2.
1.112 s
OK
1.
0.288 s
OK
2.
0.288 s
OK
1.
0.468 s
OK
2.
0.164 s
OK
1.
0.164 s
OK
2.
0.164 s
OK
1.
0.568 s
OK
2.
0.612 s
OK
1.
1.064 s
OK
2.
1.052 s
OK