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53. Maximum Subarray

Easy

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

A subarray is a contiguous part of an array.

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 = [5,4,-1,7,8]

Output: 23

Constraints:

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.

Solution

public class Solution {
    public int MaxSubArray(int[] nums) {
        int maxSum = nums[0];
        int curSum = 0;
        for (int i = 0; i < nums.Length; i++) {
            curSum += nums[i];
            maxSum = Math.Max(curSum, maxSum);
            if (curSum < 0) {
                curSum = 0;
            }
        }
        return maxSum;
    }
}