mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
44 lines
1.0 KiB
C++
44 lines
1.0 KiB
C++
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#include <iostream>
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#include <cstdio>
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#include <vector>
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#include <cstring>
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#include <queue>
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#define maxn 10010
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using namespace std;
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int n,m,a,b;
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int pre[maxn];
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vector <int> map[maxn];
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bool vis[maxn];
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int solve(){
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queue <int> q;
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memset(vis,0,sizeof(vis));
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memset(pre,0,sizeof(pre));
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vis[1] = 1;
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q.push(1);
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int ans = 0;
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while(!q.empty()){
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int now = q.front();
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q.pop();
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for(int i = 0; i < map[now].size(); i ++)
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pre[map[now][i]] = now;
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for(int i = 1; i <= n;i ++)
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if(!vis[i] && pre[i] != now)
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vis[i] = true, q.push(i),ans ++;
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}
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return ans;
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}
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int main(){
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int ca = 1;
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while(~scanf("%d%d",&n,&m) && (n || m)){
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for(int i = 1; i <= n; i ++)
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map[i].clear();
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for(int i = 0; i < m; i ++){
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scanf("%d%d",&a,&b);
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map[a].push_back(b);
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map[b].push_back(a);
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}
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printf("Case %d: %d\n",ca ++ ,solve());
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}
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return 0;
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}
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