43 lines
1.1 KiB
C++
43 lines
1.1 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <cstring>
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using namespace std;
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bool vis[2010];
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int num[2010];
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int main(){
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int n;
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int t1,t2;
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bool flag;
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char a[7000];
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while(~scanf("%d",&n)){
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memset(num,0,sizeof(num));
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flag=1;
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for(int i=1;i<=n-1;i++){
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memset(vis,0,sizeof(vis));
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for(int j=1;j<=n/2;j++){
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scanf("%d-%d",&t1,&t2);
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if(vis[t1]||vis[t2]){
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flag=0;
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}
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vis[t1]=1;
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vis[t2]=1;
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num[t1]++;
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num[t2]++;
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}
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}
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if(flag){
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for(int i=1;i<=n;i++){
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if(num[i]!=n-1){
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flag=0;
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break;
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}
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}
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}
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if(flag)
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cout<<"Yes"<<endl;
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else
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cout<<"No"<<endl;
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}
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return 0;
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}
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