152. 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.

Similar: 53. Maximum Subarray

198. House Robber

238. Product of Array Except Self

 

public class Solution {
    public int maxProduct(int[] nums) {
        if (nums.length < 1) return 0;
        int max = nums[0];
        int maxPre = nums[0]; // the max product include current val
        int minPre = nums[0]; // the min product include current val
        for (int i = 1; i < nums.length; i++) {
            int tmp1 = maxPre * nums[i];
            int tmp2 = minPre * nums[i];
            maxPre = Math.max(nums[i], Math.max(tmp1, tmp2));
            minPre = Math.min(nums[i], Math.min(tmp1, tmp2));
            max = max > maxPre ? max : maxPre;
        }
        return max;
    }
}