题解 100% AC

#include<iostream>
using namespace std;
int dx[4]={0,1,0,-1},dy[4]={1,0,-1,0};
int n,m,minsum=1e9,sx,sy,fx,fy;
char a[50][50];
bool vis[50][50],flag;
void dfs(int x,int y,int sum){
    if(x==fx&&y==fy){
        flag=1;
        minsum=min(minsum,sum);
        return;
    }
    for(int i=0;i<4;i++){
        int nx=x+dx[i],ny=y+dy[i];
        if(nx<1||ny<1||nx>n||ny>m||vis[nx][ny]||a[nx][ny]=='#') continue;
        else{
            vis[nx][ny]=1;
            if(a[nx][ny]>='1'&&a[nx][ny]<='9'){
                dfs(nx,ny,sum+a[nx][ny]-'0'+1);
            }else{
                dfs(nx,ny,sum+1); 
            }
            vis[nx][ny]=0;
        }
    }
}
int main() {
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>a[i][j];
            if(a[i][j]=='Z') sx=i,sy=j;
            if(a[i][j]=='W') fx=i,fy=j;
        }
    }
    vis[sx][sy]=1;
    dfs(sx,sy,0);
    if(flag)cout<<minsum;
    else cout<<"IMPOSSIBLE";
	return 0;
}