60 lines
1.1 KiB
C++
60 lines
1.1 KiB
C++
#include<iostream>
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#include<string>
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#include<algorithm>
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#include<cstring>
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using namespace std;
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const int maxn=2e4+5;
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int fa[maxn],cnt[maxn];
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int a[maxn],acnt;
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bool vis[maxn*2];
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int ff(int u)
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{
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int a=u,b;
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while(u!=fa[u]) u=fa[u];
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while(a!=u)
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{
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b=fa[a];
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fa[a]=u;
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a=b;
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}
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return u;
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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,m,k; scanf("%d%d%d",&n,&m,&k);
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for(int i=1;i<=n;i++) fa[i]=i;
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for(int i=0;i<k;i++)
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{
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int u,v; scanf("%d%d",&u,&v);
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fa[ff(u)]=ff(v);
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}
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for(int i=1;i<=n;i++)
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cnt[ff(i)]++;
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for(int i=1;i<=n;i++)
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if(cnt[i])
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a[acnt++]=cnt[i];
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sort(a,a+acnt);
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vis[0]=1;
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for(int i=0;i<acnt;i++)
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for(int j=n;j>=a[i];j--)
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vis[j]|=vis[j-a[i]];
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for(int i=0;;i++)
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{
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if(m-i<0&&m+i>n)
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break;
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if(m-i>=0&&vis[m-i])
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{
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printf("%d\n",m-i);
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return 0;
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}
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if(m+i<=n&&vis[m+i])
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{
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printf("%d\n",m+i);
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return 0;
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}
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}
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return 0;
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} |