63 lines
1.1 KiB
C++
63 lines
1.1 KiB
C++
#include<cstdio>
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#include<vector>
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#include<algorithm>
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using namespace std;
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const int maxn=10000+5;
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const int INF=1000000000;
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vector<int> G[maxn],ves;
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int p[maxn],d[maxn][3];
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void dfs(int u,int fa)
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{
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ves.push_back(u);
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p[u]=fa;
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for(int i=0;i<G[u].size();i++)
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{
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int v=G[u][i];
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if(v!=fa) dfs(v,u);
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}
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}
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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int n;
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while(scanf("%d",&n)==1)
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{
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for(int i=0;i<n;i++) G[i].clear();
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for(int i=0;i<n-1;i++)
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{
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int u,v;
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scanf("%d%d",&u,&v);u--;v--;
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G[u].push_back(v);
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G[v].push_back(u);
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}
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ves.clear();
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dfs(0,-1);
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for(int i=ves.size()-1;i>=0;i--)
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{
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int u=ves[i];
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d[u][0]=1;d[u][1]=0;
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for(int j=0;j<G[u].size();j++)
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{
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int v=G[u][j];
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if(v==p[u]) continue;
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d[u][0]+=min(d[v][0],d[v][1]);
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d[u][1]+=d[v][2];
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if(d[u][0]>INF) d[u][0]=INF;
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if(d[u][1]>INF) d[u][1]=INF;
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}
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d[u][2]=INF;
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for(int j=0;j<G[u].size();j++)
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{
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int v=G[u][j];
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if(v==p[u]) continue;
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d[u][2]=min(d[u][2],d[u][1]-d[v][2]+d[v][0]);
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}
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}
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printf("%d\n",min(d[0][0],d[0][2]));
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scanf("%d",&n);
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}
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return 0;
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}
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