LeetCode53 Maximum Subarray

题目：

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. （Medium）

分析：

遍历一遍，维护一个当前最大值temp，如果temp < 0，则temp = nums[i]（前面的元素和更小，不要加进去）， 否则 temp += nums[i]；

然后每个temp更新result.

代码：

 1 class Solution {
 2 public:
 3     int maxSubArray(vector<int>& nums) {
 4         if (nums.size() == 0) {
 5             return -1;
 6         }
 7         int temp = nums[0], result = nums[0];
 8         for (int i = 1; i < nums.size(); ++i) {
 9             if (temp < 0) {
10                 temp = nums[i];
11                 result = max(temp, result);
12             }
13             else {
14                 temp = nums[i] + temp;
15                 result = max(temp, result);
16             }
17         }
18         return result;
19     }
20 };

题目还有分治和动归的算法，明天再说...