$n leq 1000000$个相等或不等关系描述一些变量，问能否成立，多组数据。
走错片场？普及题误入noi
1 //#include<iostream> 2 #include<cstring> 3 #include<cstdio> 4 //#include<math.h> 5 //#include<set> 6 //#include<queue> 7 //#include<bitset> 8 //#include<vector> 9 #include<algorithm> 10 #include<stdlib.h> 11 using namespace std; 12 13 #define LL long long 14 int qread() 15 { 16 char c; int s=0,f=1; while ((c=getchar())<'0' || c>'9') (c=='-') && (f=-1); 17 do s=s*10+c-'0'; while ((c=getchar())>='0' && c<='9'); return s*f; 18 } 19 20 //Pay attention to '-' , LL and double of qread!!!! 21 22 int T,n; 23 #define maxn 2000011 24 int ufs[maxn]; 25 int find(int x) {return x==ufs[x]?x:(ufs[x]=find(ufs[x]));} 26 void Union(int x,int y) {x=find(x); y=find(y); if (x!=y) ufs[x]=y;} 27 28 #define maxh 1000007 29 struct Hash 30 { 31 struct Edge{int v,id,next;}edge[maxh]; int first[maxh],le; 32 void clear() {memset(first,0,sizeof(first)); le=1;} 33 int insert(int x) 34 { 35 int h=x%maxh; 36 for (int i=first[h];i;i=edge[i].next) if (edge[i].v==x) return edge[i].id; 37 Edge &e=edge[le]; e.v=x; e.id=le; e.next=first[h]; first[h]=le++; 38 return le-1; 39 } 40 }h; 41 42 struct Node{int x,y;}eee[maxn]; int le=0; 43 int main() 44 { 45 T=qread(); 46 while (T--) 47 { 48 n=qread(); 49 int op,x,y; h.clear(); le=0; 50 for (int i=1;i<=n+n;i++) ufs[i]=i; 51 for (int i=1;i<=n;i++) 52 { 53 x=qread(); y=qread(); op=qread(); 54 x=h.insert(x); y=h.insert(y); 55 if (!op) eee[++le]=(Node){x,y}; 56 else Union(x,y); 57 } 58 bool flag=1; 59 for (int i=1;i<=le;i++) if (find(eee[i].x)==find(eee[i].y)) flag=0; 60 if (flag) puts("YES"); else puts("NO"); 61 } 62 return 0; 63 }