拓扑排序之NOIP2003神经网络

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
const int maxn=110;
int c[maxn],u[maxn],a[maxn][maxn],w[maxn][maxn],rd[maxn],cd[maxn],q[maxn],p[maxn],pd[maxn];
int main(){
	freopen("network.in","r",stdin);
	freopen("network.out","w",stdout);
	int i,j,k,m,n,x,y,z;
	scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++)scanf("%d%d",&c[i],&u[i]);
	for(i=1;i<=m;i++){
		scanf("%d%d%d",&x,&y,&z);
		a[x][y]=1; w[x][y]=z; rd[y]++; cd[x]++;
	}
	int f=0,l=0;
	for(i=1;i<=n;i++)
		if(rd[i]==0){
			q[++l]=i;
		}
	while(f<l){
		f++;
		if(c[q[f]]<=0){
			for(i=1;i<=n;i++)
				if(!p[i] && a[q[f]][i]){
					rd[i]--;
					if(rd[i]==0)
						q[++l]=i;
				}
		}else{
			for(i=1;i<=n;i++)
				if(!p[i] && a[q[f]][i]){
					rd[i]--;
					if(rd[i]==0)
						q[++l]=i;
					c[i]+=c[q[f]]*w[q[f]][i];
					if(!pd[i]){pd[i]=1;c[i]-=u[i];}
				}
		}
		p[q[f]]=1;
	}
	int sum=0;
	for(i=1;i<=n;i++)
		if(cd[i]==0 && c[i]>0)sum++;
	if(sum==0)
		puts("NULL");
	else
		for(i=1;i<=n;i++)
			if(cd[i]==0 && c[i]>0) printf("%d %d\n",i,c[i]);
	return 0;
}