居然没更新flag就交了，错了两次。。3个题，都是一个类型。
1 #include <cstring> 2 #include <cstdio> 3 #include <string> 4 #include <iostream> 5 #include <algorithm> 6 #include <vector> 7 using namespace std; 8 int o[5001]; 9 int flag[5001]; 10 int find(int x) 11 { 12 if(x == o[x]) return x; 13 int t = find(o[x]); 14 flag[x] = (flag[x] + flag[o[x]])%2; 15 return o[x] = t; 16 } 17 int main() 18 { 19 int n,m,i,T,cas = 1,x,y,tx,ty,z; 20 scanf("%d",&T); 21 while(cas <= T) 22 { 23 scanf("%d%d",&n,&m); 24 for(i = 1; i <= n; i ++) 25 { 26 o[i] = i; 27 flag[i] = 0; 28 } 29 z = 1; 30 for(i = 0; i < m; i ++) 31 { 32 scanf("%d%d",&x,&y); 33 if(z) 34 { 35 tx = find(x); 36 ty = find(y); 37 if(tx != ty) 38 { 39 o[tx] = ty; 40 flag[tx] = (flag[y] - flag[x] + 3)%2; 41 } 42 else if(tx == ty) 43 { 44 if(flag[x] == flag[y]) 45 z = 0; 46 } 47 } 48 } 49 printf("Scenario #%d: ",cas++); 50 if(z) 51 printf("No suspicious bugs found! "); 52 else 53 printf("Suspicious bugs found! "); 54 if(cas <= T) printf(" "); 55 } 56 return 0; 57 }