Given an integer array nums, find the subarray with the largest sum, and return its sum.
Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: The subarray [4,-1,2,1] has the largest sum 6.
Topics: arrays, dp
Asked by: Amazon, Google, Meta, Microsoft, Apple, Adobe, Bloomberg
Time complexity: O(n). Space complexity: O(1).