hduAnother Graph Game

http://acm.hdu.edu.cn/showproblem.php?pid=4647

很扯的一题 将每条边的一半权值分给它所连的两个结点

#include <iostream>
#include<cstdio>
#include<cstring>
#include<stdlib.h>
#include<algorithm>
using namespace std;
double a[100010];
int main()
{
    int i,j,n,m,u,v;
    while(cin>>n>>m)
    {
        for(i = 1; i <= n ;i++)
        cin>>a[i];
        double s;
        for(i = 1; i <= m ; i++)
        {
            scanf("%d%d%lf",&u,&v,&s);
            a[u]+=s/2;
            a[v]+=s/2;
        }
        sort(a+1,a+n+1);
        double s1=0,s2=0;
        for(i = 1; i <= n ;i++)
        {
            if(i%2!=0)
            s1+=a[i];
            else
            s2+=a[i];
        }
        long long k = max(s1,s2)-min(s1,s2);
        cout<<k<<endl;
    }
    return 0;
}