[LeetCode] 53. Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.
For example, given the array [-2,1,-3,4,-1,2,1,-5,4],
the contiguous subarray [4,-1,2,1] has the largest sum = 6.
click to show more practice.
More practice:
If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

Thought process:
Iterate through the array and keep track of the maximum subarray that ends at current index. Update the global max based on current rolling max.

Solution:
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public class Solution {
    public int maxSubArray(int[] nums) {
        int max = Integer.MIN_VALUE;
        int maxEndingHere = 0;
        
        for (int num : nums) {
            maxEndingHere = Math.max(maxEndingHere + num, num);
            max = Math.max(max, maxEndingHere);
        }
        
        return max;
    }
}

Time complexity: O(n).
Location: San Jose, CA, USA

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