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.

计算子数列的最大和，设定一个x，x目前为止的最大值，y为部分数的和，y从第一位开始，逐次求其与后一位的和，一旦y<0，则y归零，每一次取得的y值与x进行比较，如果y>x，则x=y,否则继续。当所有的数都进行运算之后，x的值即为所求。

#include<vector>
#include<iostream>

using namespace std;

int maxSubArray(vector<int>& nums) {
    int a = nums[0];
    int x,y,sum = 0;
int num = nums.size();
for(int b = 0; b < num; b++){
        sum += nums[b];
        a = max(sum, a);
        sum = max(sum, 0);
}
return a;
}

int main()
{
vector<int> nums;
int c, n;
cin >> n;
for(int a = 0; a < n; a++){
cin >> c;
nums.push_back(c) ; 
}
int b = maxSubArray(nums); 
cout << b ;
return 0;
}