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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define maxx 100009
  4. #define pb push_back
  5. #define pii pair<int,int>
  6. queue<int>q;
  7. vector<pii>vpii[maxx];
  8. #define inf 0x7fffffff
  9. int X[]={+2,+2,-2,-2,+1,-1,-1,+1};
  10. int Y[]={-1,+1,-1,+1,+2,+2,-2,-2};
  11. map<char,int>cost;
  12. vector<int>v[maxx];
  13. int vis[maxx];
  14. enum{notvisited,black,white};
  15. int b=0,w=0;
  16. void bfs(int src)
  17. {
  18.     vis[src]=black;
  19.     b++;
  20.     queue<int>q;
  21.     q.push(src);
  22.     while(!q.empty()){
  23.       int s=q.front();
  24.       q.pop();
  25.     for(int i=0;i<v[s].size();i++){
  26.  
  27.         if(vis[v[s][i]]==notvisited)
  28.         {
  29.             if(vis[s]==black)
  30.             {
  31.                 vis[v[s][i]]=white;
  32.                 w++;
  33.             }
  34.             else if(vis[s]==white)
  35.             {
  36.                 vis[v[s][i]]=black;
  37.                 b++;
  38.             }
  39.             q.push(v[s][i]);
  40.         }
  41.       }
  42.    }
  43. }
  44. int main() {
  45.      int n;
  46.      scanf("%d",&n);
  47.      int m=n-1,x;
  48.      while(m--){
  49.         int a,b;
  50.         scanf("%d %d",&a,&b);
  51.         v[a].pb(b);
  52.         v[b].pb(a);
  53.         x=a;
  54.      }
  55.      bfs(x);
  56.      printf("%d\n",min(b,w));
  57. 	return 0;
  58. }
  59.  
Runtime error #stdin #stdout 0s 6008KB
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Standard input is empty
stdout
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Standard output is empty
https://ideone.com/Cz4WUm
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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