Max double slice sum

Question

Recently, I tried to solve the Max Double Slice Sum problem in codility which is a variant of max slice problem. My Solution was to look for a slice that has maximum value w

Answer 1

Using the idea from http://en.wikipedia.org/wiki/Maximum_subarray_problem and Abhishek Bansal's answer above. 100% test pass:

public class Solution {

public int solution(int[] A) {
    int[] maxEndingHere = maxEndingHere(A);
    int[] maxStartingHere = maxStartingHere(A);
    int maxSlice = 0;
    for (int i = 1; i < A.length-1;i++) {
      maxSlice = Math.max(maxSlice, maxEndingHere[i-1]+maxStartingHere[i+1]);
    }
    return maxSlice;
}


/**
 * Precalculate ending subarrays. Take into account that first and last element are always 0
 * @param input
 * @return
 */
public static int[] maxEndingHere(int[] input) {
    int[] result = new int[input.length];
    result[0] = result[input.length-1] = 0;
    for (int i = 1; i < input.length-1; i++) {
        result[i] = Math.max(0, result[i-1] + input[i]);
    }
    return result;
}

/**
 * Precalculate starting subarrays. Take into account that first and last element are always 0
 * @param input
 * @return
 */
public static int[] maxStartingHere(int[] input) {
    int[] result = new int[input.length];
    result[0] = result[input.length-1] = 0;
    for (int i = input.length-2; i >= 1; i--) {
        result[i] = Math.max(0, result[i+1] + input[i]);
    }
    return result;
}

}