hdu 4647——Another Graph Game

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
double a[110000];
bool cmp(double x,double y)
{
	return x>y;
}
int main()
{
	int n,m;
	while(cin>>n>>m)
	{
		for(int i=1;i<=n;i++)
			scanf("%lf",&a[i]);
		int x,y;
		double z;
		while(m--)
		{
			scanf("%d%d%lf",&x,&y,&z);
			if(x!=y)
			{
				a[x]+=z/2.0;
				a[y]+=z/2.0;
			}
			else
				a[x]+=z;//注意自环 
		}
		sort(a+1,a+1+n,cmp);
		double ans=0;
		for(int i=1;i<=n;i+=2)
			ans+=a[i]-a[i+1];
		printf("%.0f\n",ans);			
	}
	return 0;
}