Tasks Details
easy
1.
TieRopes
Tie adjacent ropes to achieve the maximum number of ropes of length >= K.
Task Score
12%
Correctness
25%
Performance
0%
There are N ropes numbered from 0 to N − 1, whose lengths are given in an array A, lying on the floor in a line. For each I (0 ≤ I < N), the length of rope I on the line is A[I].
We say that two ropes I and I + 1 are adjacent. Two adjacent ropes can be tied together with a knot, and the length of the tied rope is the sum of lengths of both ropes. The resulting new rope can then be tied again.
For a given integer K, the goal is to tie the ropes in such a way that the number of ropes whose length is greater than or equal to K is maximal.
For example, consider K = 4 and array A such that:
A[0] = 1 A[1] = 2 A[2] = 3 A[3] = 4 A[4] = 1 A[5] = 1 A[6] = 3The ropes are shown in the figure below.
We can tie:
- rope 1 with rope 2 to produce a rope of length A[1] + A[2] = 5;
- rope 4 with rope 5 with rope 6 to produce a rope of length A[4] + A[5] + A[6] = 5.
After that, there will be three ropes whose lengths are greater than or equal to K = 4. It is not possible to produce four such ropes.
Write a function:
class Solution { public int solution(int K, int[] A); }
that, given an integer K and a non-empty array A of N integers, returns the maximum number of ropes of length greater than or equal to K that can be created.
For example, given K = 4 and array A such that:
A[0] = 1 A[1] = 2 A[2] = 3 A[3] = 4 A[4] = 1 A[5] = 1 A[6] = 3the function should return 3, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [1..100,000];
- K is an integer within the range [1..1,000,000,000];
- each element of array A is an integer within the range [1..1,000,000,000].
Copyright 2009–2025 by Codility Limited. All Rights Reserved. Unauthorized copying, publication or disclosure prohibited.
Solution
Programming language used Java 8
Time spent on task 16 minutes
Notes
not defined yet
Code: 13:24:35 UTC,
java,
autosave
Code: 13:24:42 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 K, int[] A) {
// write your code in Java SE 8
int maxCnt = 0;
if (IntStream.of(A).sum() < K) {
return 0;
}
for (int i=0; i<A.length; i++) {
// if (A[i] >= K) {
// continue;
// }
int j = i+1;
int sum = A[i];
int cnt = 1;
while (j < A.length && sum <= K) {
sum += A[j];
j++;
maxCnt++;
}
// maxCnt = Math.max(maxCnt, cnt);
}
return maxCnt;
}
}
Code: 13:24:47 UTC,
java,
verify,
result: Failed
// you can also use imports, for example:
// import java.util.*;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int K, int[] A) {
// write your code in Java SE 8
int maxCnt = 0;
if (IntStream.of(A).sum() < K) {
return 0;
}
for (int i=0; i<A.length; i++) {
// if (A[i] >= K) {
// continue;
// }
int j = i+1;
int sum = A[i];
int cnt = 1;
while (j < A.length && sum <= K) {
sum += A[j];
j++;
maxCnt++;
}
// maxCnt = Math.max(maxCnt, cnt);
}
return maxCnt;
}
}
Analysis
expand all
Example tests
1.
0.120 s
WRONG ANSWER,
got 8 expected 3
Code: 13:40:14 UTC,
java,
autosave
// you can also use imports, for example:
// import java.util.*;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int K, int[] A) {
// write your code in Java SE 8
int maxCnt = 0;
if (IntStream.of(A).sum() < K) {
return 0;
}
for (int i=0; i<A.length; i++) {
int j = i+1;
int sum = A[i];
while (j < A.length && sum <= K) {
sum += A[j];
j++;
}
maxCnt++;
i = j-1;
// maxCnt = Math.max(maxCnt, cnt);
}
//System.out.println(maxCnt);
return maxCnt;
}
}
Code: 13:40:16 UTC,
java,
verify,
result: Passed
// you can also use imports, for example:
// import java.util.*;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int K, int[] A) {
// write your code in Java SE 8
int maxCnt = 0;
if (IntStream.of(A).sum() < K) {
return 0;
}
for (int i=0; i<A.length; i++) {
int j = i+1;
int sum = A[i];
while (j < A.length && sum <= K) {
sum += A[j];
j++;
}
maxCnt++;
i = j-1;
// maxCnt = Math.max(maxCnt, cnt);
}
//System.out.println(maxCnt);
return maxCnt;
}
}
Analysis
Code: 13:40:20 UTC,
java,
final,
score:
12
// you can also use imports, for example:
// import java.util.*;
import java.util.stream.IntStream;
// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");
class Solution {
public int solution(int K, int[] A) {
// write your code in Java SE 8
int maxCnt = 0;
if (IntStream.of(A).sum() < K) {
return 0;
}
for (int i=0; i<A.length; i++) {
int j = i+1;
int sum = A[i];
while (j < A.length && sum <= K) {
sum += A[j];
j++;
}
maxCnt++;
i = j-1;
// maxCnt = Math.max(maxCnt, cnt);
}
//System.out.println(maxCnt);
return maxCnt;
}
}
Analysis summary
The following issues have been detected: wrong answers, timeout errors.
Analysis
expand all
Correctness tests
1.
0.088 s
OK
2.
0.088 s
OK
3.
0.088 s
OK
4.
0.088 s
OK
5.
0.088 s
OK
1.
0.088 s
WRONG ANSWER,
got 1 expected 2
2.
0.084 s
OK
3.
0.088 s
OK
4.
0.088 s
OK
5.
0.088 s
OK
1.
0.084 s
WRONG ANSWER,
got 3 expected 2
2.
0.088 s
OK
1.
0.088 s
WRONG ANSWER,
got 0 expected 36
2.
0.084 s
WRONG ANSWER,
got 38 expected 41
expand all
Performance tests
medium_random
chaotic medium sequences length = ~5,000
chaotic medium sequences length = ~5,000
✘
TIMEOUT ERROR
running time: 0.104 sec., time limit: 0.100 sec.
running time: 0.104 sec., time limit: 0.100 sec.
1.
0.104 s
TIMEOUT ERROR,
running time: 0.104 sec., time limit: 0.100 sec.
2.
0.096 s
WRONG ANSWER,
got 662 expected 723
3.
0.096 s
WRONG ANSWER,
got 15 expected 14
1.
0.260 s
WRONG ANSWER,
got 9286 expected 10000
2.
0.256 s
OK
3.
0.348 s
WRONG ANSWER,
got 98710 expected 98711
1.
0.464 s
WRONG ANSWER,
got 0 expected 100000
2.
0.472 s
OK
3.
0.308 s
OK
4.
0.440 s
WRONG ANSWER,
got 0 expected 36752
1.
0.256 s
OK
2.
0.256 s
OK
3.
0.164 s
OK
4.
0.260 s
WRONG ANSWER,
got 275 expected 274