Tempter of the Bone(HDU 深搜）

題目鏈接

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <string>
#include <cmath>
#include <queue>
using namespace std;
int n, m, t;
int flag;
int sx, sy, dx, dy;
char maze[8][8];
int vis[8][8];
int mv[4][2] = {{0, 1},{1, 0},{-1, 0}, {0, -1}};
void dfs(int x, int y, int time)
{
    if(x == dx && y == dy)
    {
        if(time == t)
          flag = 1;
    }
    else
    {
        if(flag == 1)
            return;
        int i;
        for(i = 0; i < 4; i++)
        {
            int tx = x + mv[i][0];
            int ty = y + mv[i][1];
            if(tx >= 0 && tx < n && ty >= 0 && ty < m && !vis[tx][ty] && (maze[tx][ty] == '.' || maze[tx][ty] == 'D'))
            {
                vis[tx][ty] = 1;
                dfs(tx, ty, time+1);
                vis[tx][ty] = 0;
            }
        }
    }
}
int main()
{
    int i, j;
    while(cin >> n >> m >> t)
    {
        if(!n && !m && !t)
            break;
            flag = 0;
        for(i = 0; i < n; i++)
        {
            cin >> maze[i];
            for(j = 0; j < m; j++)
            {
                if(maze[i][j] == 'S')
                {
                    sx = i; sy = j;
                }
                if(maze[i][j] == 'D')
                {
                    dx = i; dy = j;
                }
            }
        }
        memset(vis, 0, sizeof(vis));
        vis[sx][sy] = 1;
        dfs(sx, sy, 0);
        if(flag == 1)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}