leetcode刷题 总结，记录，备注 53

leetcode刷题53

Maximum Subarray

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

.
注意！这个题目与PAT上那个最大子列和有点区别，PAT上那个题是如果都为负数的话，最大和为0，这题并没有这样的提示，所以如果使用跟那题同样的线性时间的算法，需要在逻辑顺序上进行改动，先与最大的max比较，然后再进行与0的比较，进行置0，下面是代码

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int sum = *nums.begin(), cur = 0;
        vector<int>::iterator it;
        for (it = nums.begin(); it != nums.end(); ++it)
        {
            cur += *it;
            if (cur > sum)
            sum = cur;
            if (cur < 0)
            cur = 0;
        }
        
        return sum;
    }
};

额外要求里有更难的方法，，，暂且搁置。。。