LeetCode-152.Maximum Product Subarray

Given an integer array nums, find the contiguous subarray within an array (containing at least one number) which has the largest product.

Example 1:

Input: [2,3,-2,4]
Output: 6
Explanation: [2,3] has the largest product 6.

Example 2:

Input: [-2,0,-1]
Output: 0
Explanation: The result cannot be 2, because [-2,-1] is not a subarray.

使用动态规划，但是要注意，避免正负数出错，应该保存当前最大值和当前最小值 如[-2,3,-4]

public int maxProduct(int[] nums) {//dp mytip
        if(null==nums||0==nums.length){
            return 0;
        }
        int max = nums[0];
        int min = nums[0];
        int re = nums[0];
        for(int i=1;i<nums.length;i++){//max=Max(max*nums[i],min*nums[i],nums[i])
//min=Min(max*nums[i],min*nums[i],nums[i])
            int p = max*nums[i];
            int q = min*nums[i];
            if(p>q){
                max = p;
                min = q;
            }
            else{
                min =p;
                max = q;
            }
            max = max>nums[i]?max:nums[i];
            min = min>nums[i]?nums[i]:min;
            re = re>max?re:max;
        }
        return re;
    }