103 lines
2.7 KiB
C++
103 lines
2.7 KiB
C++
#include <cstdio>
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#include <cstring>
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#include <iostream>
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#include <algorithm>
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#include <vector>
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using namespace std;
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#define inf (1<<29)
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const int maxn = 105;
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int g[maxn][maxn],a[maxn][maxn],p[maxn];
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bool vis[maxn],combine[maxn],par[maxn];
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int d[maxn],node[maxn],st[maxn],k,s,t;
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vector <int> vst[maxn];
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vector <int> pa , pb;
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int prim(int n) {
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memset(vis,0,sizeof(vis));
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memset(d,0,sizeof(d));
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int mincut = 0 , tmp = -1;
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s = t = -1;
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int top = 0;
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for(int i=0;i<k;i++) {
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int maxi = -inf;
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for(int j=0;j<k;j++) {
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int u = node[j];
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if(!combine[u]&&!vis[u]&&d[u]>maxi) {
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tmp = u;
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maxi = d[u];
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}
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}
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st[top++] = tmp;
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vis[tmp] = true;
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if(i == k-1)
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mincut = d[tmp];
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for(int j=0;j<k;j++) {
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int u = node[j];
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if(!combine[u]&&!vis[u])
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d[u] += g[tmp][u];
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}
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}
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s = st[top-2];
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t = st[top-1];
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for(int i=0;i<top;i++) node[i] = st[i];
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return mincut;
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}
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int stoer_wagner(int n) {
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for(int i=0;i<n;i++) {
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vst[i].clear();
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vst[i].push_back(i);
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}
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int ans = inf;
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memset(combine,0,sizeof(combine));
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for(int i=0;i<n;i++) node[i] = i;
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for(int i=1;i<n;i++) {
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k = n - i + 1;
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int cur = prim(n);
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if(cur < ans) {
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ans = cur;
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for(int j=0;j<n;j++) par[j] = 0;
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for(int j=0;j<vst[t].size();j++) par[ vst[t][j] ] = 1;
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}
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combine[t] = true;
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for(int j=0;j<vst[t].size();j++) vst[s].push_back(vst[t][j]);
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for(int j=0;j<n;j++) {
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if(j == s) continue;
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if(!combine[j]) {
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g[s][j] += g[t][j];
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g[j][s] += g[j][t];
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}
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}
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}
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pa.clear(); pb.clear();
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for(int i=0;i<n;i++)
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if(par[i]) pa.push_back(i);
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else pb.push_back(i);
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return ans;
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}
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int K;
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int dfs(vector <int> t) {
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int n = t.size();
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for(int i=0;i<n;i++) for(int j=0;j<n;j++) g[i][j] = a[t[i]][t[j]];
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if(stoer_wagner(n) >= K) return 1;
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vector <int> x , y;
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for(int i=0;i<pa.size();i++) x.push_back(t[pa[i]]);
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for(int i=0;i<pb.size();i++) y.push_back(t[pb[i]]);
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return dfs(x) + dfs(y);
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}
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int main() {
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int n , m;
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while(~scanf("%d%d%d",&n,&m,&K)) {
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memset(a , 0 ,sizeof(a));
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while(m--) {
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int u , v;
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scanf("%d%d",&u,&v);
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u --; v --;
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a[u][v] += 1;
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a[v][u] += 1;
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}
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vector <int> t;
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for(int i=0;i<n;i++) t.push_back(i);
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printf("%d\n" , dfs(t));
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}
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return 0;
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}
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