LeetCode 53. Maximum Subarray

问题描述：

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.

思路动态规划，动态规划核心即找到状态转移方程。

状态转移方程也很简单：

local[i+1] = max(local[i] + a[i+1],a[i+1]);global[i+1] = max(global[i] + a[i+1],global[i]);

即分别用两个变量保存局部最大和全局最大。

AC代码如下：

class Solution {public:    int maxSubArray(vector<int>& nums)     {        int sumLocal = nums[0];        int sumGlobal = nums[0];        for(int i = 1;i < nums.size();i++)        {            sumLocal = max(sumLocal + nums[i],nums[i]);            sumGlobal = max(sumGlobal,sumLocal);        }        return sumGlobal;    }};