hdu 3498
DLX 重復覆蓋模板題
# include<cstdio> # include<cstring> #include<iostream> #include<vector> using namespace std; # define N 60 # define V N*N int L[V],R[V];//記錄左右方向的雙向鏈表 int U[V],D[V];//記錄上下方向的雙向鏈表 int C[V];//指向其列指針頭的地址 int H[N];//行指針頭 int S[N];//記錄列鏈表中節點的總數 int size,n,m,ak; int visit[N]; vector<int >g[N];void Link(int r,int c) {S[c]++;C[size]=c;U[size]=U[c];D[U[c]]=size;D[size]=c;U[c]=size;if(H[r]==-1) H[r]=L[size]=R[size]=size;else{L[size]=L[H[r]];R[L[H[r]]]=size;R[size]=H[r];L[H[r]]=size;}size++; } void remove(int Size) {int j;for(j=D[Size];j!=Size;j=D[j])L[R[j]]=L[j],R[L[j]]=R[j]; } void resume(int Size) {int j;for(j=D[Size];j!=Size;j=D[j])L[R[j]]=R[L[j]]=j; } int h() {int count=0,i,j,k;memset(visit,0,sizeof(visit));for(i=R[0];i;i=R[i]){if(visit[i]) continue;count++;for(j=D[i];j!=i;j=D[j]){for(k=R[j];k!=j;k=R[k])visit[C[k]]=1;}}return count; } void Dance(int k) {int i,j,min,c;if(k+h()>=ak) return;if(!R[0]){if(k<ak) ak=k;return;}for(min=N,i=R[0];i;i=R[i])if(min>S[i]) min=S[i],c=i;for(i=D[c];i!=c;i=D[i]){remove(i);for(j=R[i];j!=i;j=R[j])remove(j);Dance(k+1);for(j=R[i];j!=i;j=R[j])resume(j);resume(i);} } int main() {int i,j;while(scanf("%d%d",&n,&m)!=EOF){for(i=0;i<=n;i++){g[i].clear();g[i].push_back(i);S[i]=0;U[i]=D[i]=i;L[i+1]=i;R[i]=i+1;}R[n]=0;size=n+1;memset(H,-1,sizeof(H));for(i=0;i<m;i++){int a,b;scanf("%d%d",&a,&b);g[a].push_back(b); g[b].push_back(a);}for(i=1;i<=n;i++){for(j=0;j<g[i].size();j++){Link(i,g[i][j]);}} ak=n;Dance(0);printf("%d\n",ak);}return 0; }總結
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