152.MaxProduct.cs

// 152. Maximum Product Subarray

// Given an integer array nums, find a subarray
// that has the largest product, and return the product.

// The test cases are generated so that the answer will fit in a 32-bit integer.

// Example 1:
// Input: nums = [2,3,-2,4]
// Output: 6
// Explanation: [2,3] has the largest product 6.
// Example 2:
// Input: nums = [-2,0,-1]
// Output: 0
// Explanation: The result cannot be 2, because [-2,-1] is not a subarray.

// Constraints:
// 1 <= nums.length <= 2 * 104
// -10 <= nums[i] <= 10
// The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.

public class Solution {
    public int MaxProduct(int[] nums) {
        int max = nums[0], min = nums[0], product = nums[0];
        for(int i = 1; i < nums.Length; i++){
            int temp = Math.Max(nums[i], Math.Max(nums[i]*max, nums[i]*min));
            min = Math.Min(nums[i], Math.Min(nums[i]*max, nums[i]*min));
            max = temp;
            product = Math.Max(max,product);
        }
        return product;
    }
}