题解 | #连续子数组的最大乘积#

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param nums int整型vector 
     * @return int整型
     */
    int maxProduct(vector<int>& nums) {
        // write code here
        int n = nums.size();
        vector<int> dp_pos(n, 0);
        vector<int> dp_neg(n, 0);
        dp_pos[0] = nums[0];
        dp_neg[0] = nums[0];
        int res = nums[0];
        
        for(int i=1; i<n; i++){
            dp_pos[i] = max(dp_pos[i-1]*nums[i], nums[i]);
            dp_pos[i] = max(dp_neg[i-1]*nums[i], dp_pos[i]);
            dp_neg[i] = min(dp_neg[i-1]*nums[i], nums[i]);
            dp_neg[i] = min(dp_pos[i-1]*nums[i], dp_neg[i]);
            
            res = max(res, dp_pos[i]);
        }
        return res;
    }
};