124 lines
2.7 KiB
C++
124 lines
2.7 KiB
C++
# include<stdio.h>
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# include<string.h>
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# define N 200
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# define V 900
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int n,m,size,ak;
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int U[V],D[V];
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int L[V],R[V];
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int C[V];
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int H[N],S[N];
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int visit[17][17];
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int rr,cc;
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char map[17][17];
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void Link(int r,int c)
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{
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S[c]++;C[size]=c;
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U[size]=U[c];D[U[c]]=size;
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D[size]=c;U[c]=size;
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if(H[r]==-1) H[r]=L[size]=R[size]=size;
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else
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{
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L[size]=L[H[r]];R[L[H[r]]]=size;
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R[size]=H[r];L[H[r]]=size;
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}
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size++;
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}
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void remove(int c)
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{
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int i;
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for(i=D[c];i!=c;i=D[i])
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L[R[i]]=L[i],R[L[i]]=R[i];
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}
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void resume(int c)
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{
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int i;
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for(i=U[c];i!=c;i=U[i])
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L[R[i]]=R[L[i]]=i;
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}
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int h()
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{
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int i,j,k,count=0;
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bool hash[N];
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memset(hash,0,sizeof(hash));
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for(i=R[0];i;i=R[i])
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{
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if(hash[i]) continue;
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hash[i]=1;
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count++;
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for(j=D[i];j!=i;j=D[j])
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for(k=R[j];k!=j;k=R[k])
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hash[C[k]]=1;
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}
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return count;
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}
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void Dance(int k)
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{
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int i,j,Min,c;
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if(h()+k>=ak) return;
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if(!R[0])
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{
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if(k<ak) ak=k;
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return;
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}
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for(Min=N,i=R[0];i;i=R[i])
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if(Min>S[i]) Min=S[i],c=i;
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for(i=D[c];i!=c;i=D[i])
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{
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remove(i);
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for(j=R[i];j!=i;j=R[j])
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remove(j);
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Dance(k+1);
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for(j=L[i];j!=i;j=L[j])
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resume(j);
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resume(i);
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}
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}
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int main()
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{
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int i,j,k1,k2;
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while(scanf("%d%d",&n,&m)!=EOF)
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{
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cc=0;
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memset(visit,0,sizeof(visit));
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for(i=0;i<n;i++)
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{
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scanf("%s",map[i]);
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for(j=0;map[i][j];j++)
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if(map[i][j]=='#') visit[i][j]=++cc;
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}
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for(i=0;i<=cc;i++)
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{
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S[i]=0;
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D[i]=U[i]=i;
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L[i+1]=i;R[i]=i+1;
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}R[cc]=0;
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size=cc+1;
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memset(H,-1,sizeof(H));
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rr=0;
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for(i=1;i<n-1;i++)
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{
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for(j=1;j<m-1;j++)
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if(map[i][j]=='.')
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{
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rr++;
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k1=i-1;k2=j;
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while(map[k1][k2]=='.') k1--;
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if(map[k1][k2]=='#') Link(rr,visit[k1][k2]);
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k1=i+1;k2=j;
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while(map[k1][k2]=='.') k1++;
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if(map[k1][k2]=='#') Link(rr,visit[k1][k2]);
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k1=i;k2=j-1;
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while(map[k1][k2]=='.') k2--;
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if(map[k1][k2]=='#') Link(rr,visit[k1][k2]);
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k1=i;k2=j+1;
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while(map[k1][k2]=='.') k2++;
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if(map[k1][k2]=='#') Link(rr,visit[k1][k2]);
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}
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}
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ak=N;
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Dance(0);
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printf("%d\n",ak);
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}
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return 0;
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}
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