Today I have done leetcode's December LeetCoding Challenge with cpp.

December LeetCoding Challenge 3

Description

Maximum Product Subarray

Given an integer array nums, find a contiguous non-empty subarray within the array that has the largest product, and return the product.

It is guaranteed that the answer will fit in a 32-bit integer.

A subarray is a contiguous subsequence of the array.

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 * 10^4
• -10 <= nums[i] <= 10
• The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int maxProduct(vector<int>& nums) {
    int answer = INT_MIN;
    int l = 1;
    int r = 1;
    int len = nums.size();
    for(int i = 0; i < len; ++i) {
      l *= nums[i];
      r *= nums[len - i - 1];
      answer = max({l, r, answer});
      if(!l) l = 1;
      if(!r) r = 1;
    }
    return answer;
  }
};

// Accepted
// 187/187 cases passed (4 ms)
// Your runtime beats 81.49 % of cpp submissions
// Your memory usage beats 52.62 % of cpp submissions (11.7 MB)