MaxSliceSum.js

/**


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. The sum of a slice (P, Q) is the total of A[P] + A[P+1] + ... + A[Q].

Write a function:

    function solution(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(1), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.
**/



function solution(A) {
    var long = A.length;
    var max_sum = A[0];
    var max_value = A[0];
    var max_current = 0;
    for(i=0;i<long;i++){
        max_current = Math.max(A[i], max_current+A[i]);
        max_sum = Math.max(max_sum, max_current);
        max_value = Math.max(max_value, A[i]);
    }
    return Math.max(max_sum, max_value);
}