You are given an array A consisting of the integers −1, 0 and 1. A slice of that array is any pair of integers (P, Q) such that 0 ≤ P ≤ Q < N. Your task is to find the longest slice of A whose elements yield a non-negative sum.
Write a function:
class Solution { public int solution(int[] A); }
that, given an array A of length N, consisting only of the values −1, 0, 1, returns the length of the longest slice of A that yields a non-negative sum. If there's no such slice, your function should return 0.
For example, given A = [−1, −1, 1, −1, 1, 0, 1, −1, −1], your function should return 7, as the slice starting at the second position and ending at the eighth is the longest slice with a non-negative sum.
For another example, given A = [1, 1, −1, −1, −1, −1, −1, 1, 1] your function should return 4: both the first four elements and the last four elements of array A are longest valid slices.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [2..100,000];
- each element of array A is an integer within the range [−1..1].
// you can also use imports, for example:
// import java.util.*;
import java.util.HashMap;
// 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) {
HashMap<Integer, Integer> hM = new HashMap<Integer, Integer>();
int sum = 0;
int max_len = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
if (sum > -1)
max_len = i+1;
Integer prev_i = hM.get(sum);
if (prev_i != null)
max_len = Math.max(max_len, i-prev_i);
else
hM.put(sum, i);
}
}
}Solution.java:27: error: missing return statement
}
^
1 error
// you can also use imports, for example:
// import java.util.*;
import java.util.HashMap;
// 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) {
HashMap<Integer, Integer> hM = new HashMap<Integer, Integer>();
int sum = 0;
int max_len = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
if (sum > -1)
max_len = i+1;
Integer prev_i = hM.get(sum);
if (prev_i != null)
max_len = Math.max(max_len, i-prev_i);
else
hM.put(sum, i);
}
return max_len;
}
}// you can also use imports, for example:
// import java.util.*;
import java.util.HashMap;
// 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) {
HashMap<Integer, Integer> hM = new HashMap<Integer, Integer>();
int sum = 0;
int max_len = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
if (sum > -1)
max_len = i+1;
Integer prev_i = hM.get(sum);
if (prev_i != null)
max_len = Math.max(max_len, i-prev_i);
else
hM.put(sum, i);
}
return max_len;
}
}// you can also use imports, for example:
// import java.util.*;
import java.util.HashMap;
// 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) {
HashMap<Integer, Integer> hM = new HashMap<Integer, Integer>();
int sum = 0;
int max_len = 0;
for (int i = 0; i < A.length; i++) {
sum += A[i];
if (sum > -1)
max_len = i+1;
Integer prev_i = hM.get(sum);
if (prev_i != null)
max_len = Math.max(max_len, i-prev_i);
else
hM.put(sum, i);
}
return max_len;
}
}The solution obtained perfect score.