题解：
和上一题差不多
然后注意格式
代码：
#include<cstdio> #include<cmath> #include<algorithm> #include<cstring> const int N=25; using namespace std; struct data{int to,ne,v;}e[500001]; int r,c,d,T,cnt,ans,cas,mp[N][N],mark[N][N],q[802],h[802],fi[802]; void ins(int u,int v,int w) { cnt++;e[cnt].to=v; e[cnt].ne=fi[u]; fi[u]=cnt; e[cnt].v=w; } void insert(int u,int v,int w) { ins(u,v,w); ins(v,u,0); } int judge(int x1,int y1,int x2,int y2) { if (((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))<=(d*d)&&mp[x1][y1]&&mp[x2][y2]) return 1; return 0; } void build() { for (int x1=1;x1<=r;x1++) for (int y1=1;y1<=c;y1++) for (int x2=x1-d;x2<=x1+d;x2++) for (int y2=y1-d;y2<=y1+d;y2++) if (judge(x1,y1,x2,y2)&&(x1!=x2||y1!=y2)) insert(mark[x1][y1]+400,mark[x2][y2],1e9); for (int i=1;i<=r;i++) for (int j=1;j<=c;j++) if (mp[i][j])insert(mark[i][j],mark[i][j]+400,mp[i][j]); } int bfs() { memset(h,-1,sizeof(h)); int t=0,w=1,now; q[0]=h[0]=0; while (t<w) { now=q[t++]; for (int i=fi[now];i;i=e[i].ne) if (e[i].v&&h[e[i].to]==-1) { h[e[i].to]=h[now]+1; q[w++]=e[i].to; } } if (h[801]==-1)return 0; return 1; } int dfs(int x,int f) { if (x==801)return f; int used=0,w; for (int i=fi[x];i;i=e[i].ne) if (e[i].v&&h[e[i].to]==h[x]+1) { w=f-used;w=dfs(e[i].to,min(w,e[i].v)); e[i].v-=w;e[i^1].v+=w; used+=w; if(used==f)return f; } if (!used)h[x]=-1; return used; } void doit() { scanf("%d%d",&r,&d); char ch[N]; memset(mp,0,sizeof mp); memset(mark,0,sizeof mark); memset(fi,0,sizeof fi); memset(e,0,sizeof e); memset(q,0,sizeof q); memset(h,0,sizeof h); cnt=1; ans=0; for (int i=1;i<=r;i++) { scanf("%s",ch); c=strlen(ch); for (int j=1;j<=c;j++)mp[i][j]=ch[j-1]-'0'; } int tot=0; for (int i=1;i<=r;i++) for (int j=1;j<=c;j++) { tot++; mark[i][j]=tot; } for (int i=1;i<=r;i++) { scanf("%s",ch); for (int j=1;j<=c;j++) if (ch[j-1]=='L'){insert(0,mark[i][j],1);ans++;} } for (int i=1;i<=d;i++) for (int j=d+1;j<=r-d;j++) { insert(mark[j][i]+400,801,1e9); insert(mark[j][c-i+1]+400,801,1e9); } for (int i=1;i<=d;i++) for (int j=1;j<=c;j++) { insert(mark[i][j]+400,801,1e9); insert(mark[r-i+1][j]+400,801,1e9); } build(); while (bfs())ans-=dfs(0,1e9); printf("Case #%d: ",++cas); if (ans==0)printf("no ");else printf("%d ",ans); if (ans<2)puts("lizard was left behind."); else puts("lizards were left behind."); } int main() { scanf("%d",&T); while (T--)doit(); }