来自弱鸡的标准dfs

#include <iostream>
#include <queue>
#include <cstring>

using namespace std;
const int N = 310;
char a[N][N];
int dis[N][N];
bool st[N][N];
int T,x,y,endx,endy,n,m;

static int pos[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};

int bfs()
{

    memset(dis, 0, sizeof dis);
    memset(st,false,sizeof st);
    queue<pair<int,int>> q;
    q.push({x,y});
    dis[x][y] = 0;

    while(!q.empty())
    {
        auto tmp = q.front();
        q.pop();

        if(tmp.first == endx && tmp.second == endy)
        {
            return dis[tmp.first][tmp.second];
        }

        for(int i = 0; i < 4; i++)
        {
            int nx = tmp.first + pos[i][0];
            int ny = tmp.second + pos[i][1];
            if(nx < 0 || nx >= n || ny < 0 || ny >=m 
            || st[nx][ny] == true || a[nx][ny] == '#')
                continue;
            q.push({nx,ny});
            dis[nx][ny] = dis[tmp.first][tmp.second] + 1;
            st[nx][ny] = true;
        }
    }
    return -1;
}
int main()
{
    while(cin >> n >> m, n || m)
    {

        for(int i = 0; i < n; i++)
        {
            for(int j =0; j < m; j++)
            {
                cin >> a[i][j];
                if(a[i][j] == '@')
                {
                    x = i;
                    y = j;
                }
                if(a[i][j] == '*')
                {
                    endx = i;
                    endy = j;
                }
            }
        }
        cout << bfs() <<endl;

    }
}