LeetCode – Refresh – Maximum Product Subarray

Similar to maximum sum subarray, but need a gmin to record the global minimum to handle negative number multiplication.

class Solution {
public:
    int maxProduct(int A[], int n) {
        int result = A[0], gMax = A[0], gMin = A[0];
        for (int i = 1; i < n; i++) {
            int tmp = gMax;
            gMax = max(max(gMax*A[i], gMin*A[i]), A[i]);
            gMin = min(min(tmp*A[i], gMin*A[i]), A[i]);
            result = max(gMax, result);
        }
        return result;
    }
};