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

Question

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:

• 1 <= nums.length <= 105
• -104 <= nums[i] <= 104

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.

Python Solution

class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        if len(nums)==1:
            print(nums[0])

        global_max = nums[0]
        current_sum = nums[0]

        for i in range(1,len(nums)):
            current_sum = max(current_sum+nums[i],nums[i])
            global_max = max(current_sum,global_max)

        return global_max