#include<bits/stdc++.h>
#include<bitset>
#define int long
#define INF 0x3f3f3f3f
using namespace std;
int x=0,y,z,r,c,k=1,ans=0,cnt=0,mans=INF,mx,my,lk,kkx,kky,kkxx,kkyy;
char a;
int b;
short dis[50][50][50][50];//骑士到终点的距离 
bool sit[50][50]; 
bool king[50][50];
bool aim[50][50];//任意bfs终点 
queue<int> qx;
queue<int> qy;
vector<int> vx;
vector<int> vy;//终点位置s 
vector<int> kx;
vector<int> ky;//骑士位置 
vector<int> kdis;
//int kdis;//骑士到王的距离 
bitset<50> vis[50];
priority_queue<int,vector<int>,greater<int> > ex;//最少额外花费 
priority_queue<int,vector<int>,greater<int> > fnl;//答案 

void bfs(int x,int y)
{
	qx.push(x);qy.push(y);
	qx.push(-1);qy.push(-1);
	vis[x][y]=1;
	while(qx.front()!=-1||qx.back()!=-1)
	{
		if(sit[qx.front()][qy.front()]==1)
		{
			dis[x][y][qx.front()][qy.front()]=cnt;
			ans+=cnt;
		}			
		if(qx.front()==-1)
		{
			qx.push(-1);
			qy.push(-1);
			cnt++;
			qx.pop();
			qy.pop();
			continue;
		}
		if(qx.front()-1>0)
		{
			if(qy.front()-2>0&&vis[qx.front()-1][qy.front()-2]!=true)
			{
				qx.push(qx.front()-1);
				qy.push(qy.front()-2);
				vis[qx.front()-1][qy.front()-2]=true;
			}
			if(qy.front()+2<=r&&vis[qx.front()-1][qy.front()+2]!=true)
			{
				qx.push(qx.front()-1);
				qy.push(qy.front()+2);
				vis[qx.front()-1][qy.front()+2]=true;
			}			
		}//x-1
		if(qx.front()-2>0)
		{
			if(qy.front()-1>0&&vis[qx.front()-2][qy.front()-1]!=true)
			{
				qx.push(qx.front()-2);
				qy.push(qy.front()-1);
				vis[qx.front()-2][qy.front()-1]=true;
			}
			if(qy.front()+1<=r&&vis[qx.front()-2][qy.front()+1]!=true)
			{
				qx.push(qx.front()-2);
				qy.push(qy.front()+1);
				vis[qx.front()-2][qy.front()+1]=true;
			}			
		}//x-2
		if(qx.front()+1<=c)
		{
			if(qy.front()-2>0&&vis[qx.front()+1][qy.front()-2]!=true)
			{
				qx.push(qx.front()+1);
				qy.push(qy.front()-2);
				vis[qx.front()+1][qy.front()-2]=true;
			}
			if(qy.front()+2<=r&&vis[qx.front()+1][qy.front()+2]!=true)
			{
				qx.push(qx.front()+1);
				qy.push(qy.front()+2);
				vis[qx.front()+1][qy.front()+2]=true;
			}			
		}//x+1
		if(qx.front()+2<=c)
		{
			if(qy.front()-1>0&&vis[qx.front()+2][qy.front()-1]!=true)
			{
				qx.push(qx.front()+2);
				qy.push(qy.front()-1);
				vis[qx.front()+2][qy.front()-1]=true;
			}
			if(qy.front()+1<=r&&vis[qx.front()+2][qy.front()+1]!=true)
			{
				qx.push(qx.front()+2);
				qy.push(qy.front()+1);
				vis[qx.front()+2][qy.front()+1]=true;
			}			
		}//x+2
		qx.pop();qy.pop();
	}
}
int bfs_k(int x,int y,int p,int q)//(x,y) -> (p,q) 
{
	aim[p][q]=1;
	ans=0;cnt=0;
	qx.push(x);qy.push(y);
	qx.push(-1);qy.push(-1);
	vis[x][y]=1;
	while(qx.front()!=-1||qx.back()!=-1)
	{
		if(aim[qx.front()][qy.front()]==1)
		{
			ans=cnt;
			break;
		}
		if(qx.front()==-1)
		{
			qx.push(-1);
			qy.push(-1);
			cnt++;
			qx.pop();
			qy.pop();
			continue;
		}
		if(qx.front()-1>0)
		{
			if(qy.front()-2>0&&vis[qx.front()-1][qy.front()-2]!=true)
			{
				qx.push(qx.front()-1);
				qy.push(qy.front()-2);
				vis[qx.front()-1][qy.front()-2]=true;
			}
			if(qy.front()+2<=r&&vis[qx.front()-1][qy.front()+2]!=true)
			{
				qx.push(qx.front()-1);
				qy.push(qy.front()+2);
				vis[qx.front()-1][qy.front()+2]=true;
			}			
		}//x-1
		if(qx.front()-2>0)
		{
			if(qy.front()-1>0&&vis[qx.front()-2][qy.front()-1]!=true)
			{
				qx.push(qx.front()-2);
				qy.push(qy.front()-1);
				vis[qx.front()-2][qy.front()-1]=true;
			}
			if(qy.front()+1<=r&&vis[qx.front()-2][qy.front()+1]!=true)
			{
				qx.push(qx.front()-2);
				qy.push(qy.front()+1);
				vis[qx.front()-2][qy.front()+1]=true;
			}			
		}//x-2
		if(qx.front()+1<=c)
		{
			if(qy.front()-2>0&&vis[qx.front()+1][qy.front()-2]!=true)
			{
				qx.push(qx.front()+1);
				qy.push(qy.front()-2);
				vis[qx.front()+1][qy.front()-2]=true;
			}
			if(qy.front()+2<=r&&vis[qx.front()+1][qy.front()+2]!=true)
			{
				qx.push(qx.front()+1);
				qy.push(qy.front()+2);
				vis[qx.front()+1][qy.front()+2]=true;
			}			
		}//x+1
		if(qx.front()+2<=c)
		{
			if(qy.front()-1>0&&vis[qx.front()+2][qy.front()-1]!=true)
			{
				qx.push(qx.front()+2);
				qy.push(qy.front()-1);
				vis[qx.front()+2][qy.front()-1]=true;
			}
			if(qy.front()+1<=r&&vis[qx.front()+2][qy.front()+1]!=true)
			{
				qx.push(qx.front()+2);
				qy.push(qy.front()+1);
				vis[qx.front()+2][qy.front()+1]=true;
			}			
		}//x+2
		qx.pop();qy.pop();
	}
	aim[p][q]=0;
	while(!qx.empty()) qx.pop();
	while(!qy.empty()) qy.pop();
	for(int i=1;i<=c;i++)
		vis[i].reset();
	return ans;
}
signed main()
{
	cin>>r>>c;
	while(cin>>a>>b)
	{
		if(z==0)
		{
			z=1;
			king[b][a-'A'+1]=1;
			kkx=b;kky=a-'A'+1;
		}
		else
		{
			sit[b][a-'A'+1]=1;
			kx.push_back(b);
			ky.push_back(a-'A'+1);
		}		
	}
	if(kx.empty())
	{
		cout<<0<<endl;
		return 0;
	}
	for(int i=1;i<=c;i++)
		for(int j=1;j<=r;j++)
		{
			bfs(i,j);
			if(mans==ans)
			{
				vx.push_back(i);
				vy.push_back(j);
			}
			if(mans>ans)
			{
				mans=ans;
				mx=i;
				my=j;
				vx.clear();
				vy.clear();
				vx.push_back(i);
				vy.push_back(j);
			}			
			qx.pop();qy.pop();
			cnt=0;ans=0;
			for(int i=1;i<=c;i++)
				for(int j=1;j<=r;j++)
					vis[i][j]=0;
		}
	kkxx=kkx;kkyy=kky;
	for(int m=-5;m<=5;m++)
		for(int n=-5;n<=5;n++)
		{
			kkx=kkxx+m;
			kky=kkyy+n;
			if(kkx<1||kky<1)
			continue;
			if(kkx>r||kky>c)
			continue;
						
			for(int i=0;i<=kx.size()-1;i++)
			{
				kdis.push_back(bfs_k(kx[i],ky[i],kkx,kky));			
			}
			for(int i=0;i<=vx.size()-1;i++)
			{
				lk=bfs_k(kkx,kky,vx[i],vy[i]);
				for(int j=0;j<=kx.size()-1;j++)
				{
					ex.push(kdis[j]+lk-dis[vx[i]][vy[i]][kx[j]][ky[j]]+max(abs(m),abs(n)));		
				}
			}
			kdis.clear();
		}
	cout<<mans+ex.top()<<endl;
	return 0;
}

https://www.luogu.com.cn/record/187523714

谢谢！