dfs（主要是me不会写函数重载）

将sum也回溯即可

#include<bits/stdc++.h>
using namespace std;
int n,m,ans = 1e9;
int sx,sy,dx,dy;
char a[110][110];
bool vis[50][50];
bool flag=0;
int xx[4] = {-1,0,1,0};
int yy[4] = {0,1,0,-1};
void dfs(int x,int y,int sum){
    if(sum>ans)return ;
	if(x==dx&&y==dy){
        flag = 1;
        ans = min(sum,ans);
    	return ;
    }
    for(int i=0;i<4;i++){
    	int nx = xx[i]+x,ny = yy[i]+y;
        if(nx<1||ny<1||nx>n||ny>m)continue;
        if(vis[nx][ny])continue;
        if(a[nx][ny]=='#')continue;
        vis[nx][ny] = 1;
        if(a[nx][ny]=='.'||a[nx][ny]=='W')sum++;
        else sum+=(a[nx][ny]-'0'+1);
        dfs(nx,ny,sum);
        vis[nx][ny] = 0;
        if(a[nx][ny]=='.'||a[nx][ny]=='W')sum--;
        else sum-=(a[nx][ny]-'0'+1);
    }
}
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'){
            	dx = i;
                dy = j;
            }
        }
    }
    vis[sx][sy] = 1;
    dfs(sx,sy,0);
    if(flag){
        cout << ans;
    }
    else cout << "IMPOSSIBLE";
	return 0;
}