53. 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.

Example:

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

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.

class Solution {
    public int maxSubArray(int[] nums) {
        int n = nums.length;
        int now = nums[0];
        int ans = nums[0];
        for (int i = 1; i < n; ++i) {
            
            if (now + nums[i] < nums[i]) {
                
                now = nums[i];
            } else {
                now = now + nums[i];
            }
            
            ans = Math.max(ans, now);
            
        }
        return ans;
    }
}