53. Maximum Subarray

Medium
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.
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解題

經典 Greedy 題!
func maxSubArray(nums []int) int {
max := nums[0]
for i:=1; i<len(nums); i++ {
if nums[i-1] + nums[i] > nums[i] {
nums[i] = nums[i-1] + nums[i]
}
if nums[i] > max {
max = nums[i]
}
}
return max
}