Maximum Subarray.cpp

/*
Maximum Subarray
===============

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Follow up: If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.


Example 1:
Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.

Example 2:
Input: nums = [1]
Output: 1

Example 3:
Input: nums = [0]
Output: 0

Example 4:
Input: nums = [-1]
Output: -1

Example 5:
Input: nums = [-2147483647]
Output: -2147483647
 

Constraints:
1 <= nums.length <= 2 * 104
-231 <= nums[i] <= 231 - 1
*/

class Solution
{
public:
  int maxSubArray(vector<int> &nums)
  {
    int n = nums.size();
    if (n == 0)
      return 0;

    vector<int> dp(n, 0);
    dp[0] = nums[0];
    int ans = nums[0];

    for (int i = 1; i < n; ++i)
    {
      dp[i] = max(nums[i], nums[i] + dp[i - 1]);
      ans = max(ans, dp[i]);
    }
    return ans;
  }
};