53. Maximum Subarray

题目

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.

题目大意

给定一个整数数组 nums ，找到一个具有最大和的连续子数组（子数组最少包含一个元素），返回其最大和。

解题思路

• 这一题可以用 DP 求解也可以不用 DP。
• 题目要求输出数组中某个区间内数字之和最大的那个值。dp[i] 表示 [0,i] 区间内各个子区间和的最大值，状态转移方程是 dp[i] = nums[i] + dp[i-1] (dp[i-1] > 0)，dp[i] = nums[i] (dp[i-1] ≤ 0)。