暴力搜索 因为(最大深度较小)所以采取迭代加深策略;剩下的就是纯暴力;爆出所有待选解,判是否可行;
#include <cstdio> #include <cstring> using namespace std; const int maxn = 12; int n,m,num; char maze[maxn][maxn]; bool vis1[maxn*2],vis2[maxn*2],visi[maxn],visj[maxn]; bool dfs(int d,int st,int maxd){ if(maxd==d){ for(int i=1;i<=n;i++) for(int j=1;j<=n;j++){ if(maze[i][j]=='X'){ if(!visi[i]&&!visj[j]&&!vis1[i+j]&&!vis2[i-j+10]) return false; } } printf("%d\n",maxd); return true; } for(int j=st;j<=n;j++){ for(int i=1;i<=n;i++){ if(!visi[i]||!visj[j]||!vis1[i+j]||!vis2[i-j+10]){ int f1=0,f2=0,f3=0,f4=0; if(!visi[i]) {visi[i]=1; f1=1;} if(!visj[j]) {visj[j]=1; f2=1;} if(!vis1[i+j]){vis1[i+j]=1; f3=1;} if(!vis2[i-j+10]){vis2[i-j+10]=1; f4=1;} if(dfs(d+1,j+1,maxd)) return true; if(f1) visi[i]=0; if(f2) visj[j]=0; if(f3) vis1[i+j]=0; if(f4) vis2[i-j+10]=0; } } } return false; } int main() { int kase=1; while(scanf("%d %d",&n,&m)==2){ num=0; for(int i=1;i<=n;i++){ scanf("%s",maze[i]); for(int j=m;j>0;j--) { maze[i][j]=maze[i][j-1]; //printf if(maze[i][j]=='X') num++; } } //printf("%d\n",num); printf("Case %d: ",kase++); if(num==0) { printf("0\n"); continue; } for(int maxd=1;;maxd++){ memset(vis1,0,sizeof(vis1)); memset(vis2,0,sizeof(vis2)); memset(visi,0,sizeof(visi)); memset(visj,0,sizeof(visj)); if(dfs(0,1,maxd)) break; } } return 0; }