Maximum Product Subarray -- leetcode

Question:

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.

Answer:
DP method:

maxp(i) = max(max(maxp(i-1) * A[i], minp(i-1) * A[i] ), A[i]);
minp(i) = min(min(minp(i-1) *A[i], minp(i-1) * A[i]), A[i]);
res = max(maxp(i)) for all i.

class Solution {

public:

    int maxProduct(int A[], int n) {

        int res = A[0];

        int maxp = A[0];

        int minp = A[0];

        for (int i=1;i<n;i++){

            int tmpmax = maxp;

            int tmpmin = minp;

            maxp = max(max(tmpmax*A[i],tmpmin*A[i]),A[i]);

            minp = min(min(tmpmax*A[i],tmpmin*A[i]),A[i]);

            res = max(maxp,res);

        }

        return res;

    }

};