2.Maximum Product Subarray

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

Solution: (Dynamic Programing)

Algorithm: Keep a track of 2 variables: -> maxEnding and minEnding * For all the elements calculate the maxEnding and MinEnding * If an element is negative swap maxEnding and MinEnding

class Solution
{
public:
    int maxProduct(vector<int> &nums)
    {

        int maxTotal = nums[0];
        int maxEnding = nums[0];
        int minEnding = nums[0];

        for (int i = 1; i < nums.size(); i++)
        {
            if (nums[i] < 0)
            {
                swap(maxEnding, minEnding);
            }

            maxEnding = max(nums[i], maxEnding * nums[i]);
            minEnding = min(nums[i], minEnding * nums[i]);

            if (maxEnding > maxTotal)
            {
                maxTotal = maxEnding;
            }
        }
        return maxTotal;
    }
};

Time Complexity: O(n)