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.

class Solution {
    public int maxProduct(int[] nums) {
        if (nums == null || nums.length == 0) return 0;
        if (nums.length == 1) return nums[0];

        int min = nums[0], max = nums[0];

        int ans = nums[0];
        for (int i = 1; i < nums.length; i++){
            int newMin = Math.min(nums[i], Math.min(min * nums[i], max * nums[i]));
            int newMax = Math.max(nums[i], Math.max(min * nums[i], max * nums[i]));
            ans = Math.max(ans, Math.max(newMin, newMax));
            min = newMin;
            max = newMax;
        }

        return ans;
    }
}