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：

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

题目还有分治和动归的算法，明天再说...