53最大子序列和

DP
状态转移方程：sum[i] = max{sum[i-1]+a[i],a[i]}. (sum[i]记录以a[i]为子序列末端的最大连续和。

#include <cstdio>
#include <iostream>
#include <set>  
#include <vector>
using namespace std;

int maxSubArray(vector<int>& nums) 
{

    int sum = nums[0];
    int maxsum = nums[0];
    for (int i=1;i<nums.size();++i)
    {
        if (sum + nums[i] > nums[i])
                sum = sum + nums[i]; 
        else
                sum = nums[i];
        if (sum >maxsum)
            maxsum = sum;
    }
    return maxsum;

}
int main()
{
   vector<int> a;  
   int x;
   for(int i=0;i<2;i++)
   {
      cin>>x;
      a.push_back(x);
   }
   /*int val;
   cin>>val;
   /*for ( int ix = 0; ix < a.size(); ++ix ) 
       cout << a[ ix ] <<endl;*/
   cout<<maxSubArray(a)<<endl;
   return 0 ;
}