Codility---MaxSliceSum

Task description

A non-empty zero-indexed array A consisting of N integers is given. A pair of integers (P, Q), such that 0 ≤ P ≤ Q < N, is called a slice of array A. Thesum of a slice (P, Q) is the total of A[P] + A[P+1] + ... + A[Q].

Write a function:

class Solution { public int solution(int[] A); }

that, given an array A consisting of N integers, returns the maximum sum of any slice of A.

For example, given array A such that:

A[0] = 3 A[1] = 2 A[2] = -6 A[3] = 4 A[4] = 0

the function should return 5 because:

• (3, 4) is a slice of A that has sum 4,
• (2, 2) is a slice of A that has sum −6,
• (0, 1) is a slice of A that has sum 5,
• no other slice of A has sum greater than (0, 1).

Assume that:

• N is an integer within the range [1..1,000,000];
• each element of array A is an integer within the range [−1,000,000..1,000,000];
• the result will be an integer within the range [−2,147,483,648..2,147,483,647].

Complexity:

• expected worst-case time complexity is O(N);
• expected worst-case space complexity is O(N), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified

Solution

 

Programming language used: Java

Total time used: 25 minutes

Code: 14:21:19 UTC, java, final, score:  100

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// 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");
import java.util.Arrays;
class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
        int max_ending = A[0];
        int max_slice = A[0];
        for(int i=1; i<A.length; i++){
            max_ending = Math.max(max_ending + A[i], A[i]);
            max_slice =  Math.max(max_slice, max_ending);
        }
        return max_slice;
    }
}

https://codility.com/demo/results/trainingDWA6ZF-77M/