LeetCode[Dynamic Programming]: 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.

这类型题目适合用动态规划算法来做，由于存在负数的情况，所以不单要记录最大乘积，也要记录最小乘积。C++代码实现如下：

[code]class Solution {
public:
    int maxProduct(int A[], int n) {
        if (0 == n) return 0;

        int maxRes = A[0];
        int maxEnd = A[0];
        int minEnd = A[0];
        for (int i = 1; i < n; ++i) {
            int end1 = maxEnd * A[i], end2 = minEnd * A[i];
            maxEnd = max(A[i], max(end1, end2));
            minEnd = min(A[i], min(end1, end2));
            if (maxEnd > maxRes) maxRes = maxEnd;
        }

        return maxRes;
    }
};

时间性能如下图所示：