78 lines
1.9 KiB
C++
78 lines
1.9 KiB
C++
# include<stdio.h>
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# include<string.h>
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# include<stdlib.h>
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# define N 205
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char map[N][105];
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struct node{
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int from,to,next;
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}edge[2*N];
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int head[N],tol,visit[N],dp[N][2],dup[N][2];
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void add(int a,int b)
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{
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edge[tol].from=a;edge[tol].to=b;edge[tol].next=head[a];head[a]=tol++;
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}
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int max(int a,int b)
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{
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return a>b?a:b;
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}
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void dfs(int root)
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{
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int j,u;
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dp[root][0]=0;
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dp[root][1]=1;
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dup[root][0]=1;
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dup[root][1]=1;
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for(j=head[root];j!=-1;j=edge[j].next)
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{
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u=edge[j].to;
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dfs(u);
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dp[root][0]+=max(dp[u][0],dp[u][1]);
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dp[root][1]+=dp[u][0];
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if(dp[u][0]>dp[u][1] && dp[u][0]==0) dup[root][0]=0;
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else if(dp[u][1]>dp[u][0] && dp[u][1]==0) dup[root][0]=0;
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else if(dp[u][0]==dp[u][1]) dup[root][0]=0;
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if(dup[u][0]==0) dup[root][1]=0;
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}
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}
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int main()
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{
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int i,j,n,k,ans1,ans2;
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char str1[105],str2[105];
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while(scanf("%d",&n)!=EOF && n)
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{
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scanf("%s",map[1]);
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k=1;
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memset(head,-1,sizeof(head));
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tol=0;
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for(i=1;i<n;i++)
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{
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scanf("%s%s",str1,str2);
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ans1=ans2=-1;
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for(j=1;j<=k;j++)
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{
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if(strcmp(str1,map[j])==0) ans1=j;
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if(strcmp(str2,map[j])==0) ans2=j;
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}
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if(ans1==-1)
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{
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k++;
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ans1=k;
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strcpy(map[k],str1);
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}
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if(ans2==-1)
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{
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k++;
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ans2=k;
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strcpy(map[k],str2);
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}
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add(ans2,ans1);
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}
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memset(dp,0,sizeof(dp));
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dfs(1);
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if(dp[1][0]>dp[1][1] && dup[1][0]==1) printf("%d Yes\n",dp[1][0]);
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else if(dp[1][1]>dp[1][0] && dup[1][1]==1) printf("%d Yes\n",dp[1][1]);
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else printf("%d No\n",max(dp[1][0],dp[1][1]));
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}
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return 0;
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}
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