round4粗略地看了下。。2道数论我就不想做了（其实是要赶集地补作业）
权值并查集。。。做过食物链了再做感觉不乱了。。
然而爆0？输出调试没删掉真是日了狗了QAQ
还是先滚去搞初赛吧。。。再加上作业仍未补完= =
1 #include<bits/stdc++.h> 2 #define inc(i,l,r) for(i=l;i<=r;i++) 3 #define dec(i,l,r) for(i=l;i>=r;i--) 4 #define inf 1e9 5 #define mem(a) memset(a,0,sizeof(a)) 6 #define ll long long 7 #define succ(x) (1<<x) 8 #define NM 5000 9 using namespace std; 10 int read(){ 11 int x=0,f=1;char ch=getchar(); 12 while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();} 13 while(isdigit(ch))x=x*10+ch-'0',ch=getchar(); 14 return x*f; 15 } 16 int f[NM],a[NM],m,n,T,_x,_y,v,i,flag,fx,fy,b[NM]; 17 int find(int x){ 18 if(f[x]==x)return x; 19 int t=f[x]; 20 f[x]=find(f[x]); 21 a[x]=a[x]+a[t]-b[x]; 22 b[x]=a[f[x]]; 23 return f[x]; 24 } 25 int main(){ 26 T=read(); 27 while(T--){ 28 mem(a);mem(f);flag=false; 29 n=read();m=read(); 30 inc(i,1,n)f[i]=i; 31 inc(i,1,m){ 32 _x=read();_y=read();v=read(); 33 if(find(_x)==find(_y)){ 34 if(a[_y]-a[_x]!=v)flag=true; 35 }else{ 36 fx=find(_x);fy=find(_y); 37 f[fx]=fy;b[fx]=a[fy];a[fx]=a[fx]+a[_y]-v-a[_x]; 38 } 39 // if(flag)printf("Bessie is blind. "); 40 // else printf("Bessie's eyes are good "); 41 } 42 if(flag)printf("Bessie is blind. "); 43 else printf("Bessie's eyes are good "); 44 } 45 return 0; 46 }