LeetCode Maximum Product Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest product.

For example, given the array [2,3,-2,4],
the contiguous subarray [2,3] has the largest product = 6.

minLast[i] 表示以A[i]结尾的最小值，maxLast[i]表示以A[i]结尾的最大值。

minLast[i] = Math.min(A[i], Math.min(minLast[i - 1]*A[i], maxLast[i - 1]*A[i]));
maxLast[i] = Math.max(A[i], Math.max(maxLast[i - 1]*A[i], minLast[i - 1]*A[i]));

public class Solution {
    public int maxProduct(int[] A) {
        int length = A.length;
        if (length == 0) {
            return 0;
        }
        int[] minLast = new int[length];
        int[] maxLast = new int[length];
        minLast[0] = A[0];
        maxLast[0] = A[0];
        int res = Integer.MIN_VALUE;
        for (int i = 1; i <length ; i++) {
            minLast[i] = Math.min(A[i], Math.min(minLast[i - 1]*A[i], maxLast[i - 1]*A[i]));
            maxLast[i] = Math.max(A[i], Math.max(maxLast[i - 1]*A[i], minLast[i - 1]*A[i]));
        }
        for (int i : maxLast) {
            if (i>res) res = i;
        }
        return res;
    }
}