HDU 1010

#include <iostream>
#include <algorithm>
using namespace std;

char map[10 + 2][10 + 2];
int N, M, T, x_e, y_e;
bool ok, vis[10 + 2][10 + 2];

void dfs(int x, int y, int dist)
{    
    int temp = T - dist - abs(x - x_e)-abs(y - y_e);
    if(!dist && (temp < 0||temp & 1)) return;
    if(ok) return ;
    if(dist >= T)
    {
        if(x == x_e && y == y_e) ok = true;
        return ;
    }
    else
    {
        if((map[x - 1][y] != ‘X‘) && !vis[x - 1][y]) {vis[x - 1][y] = true; dfs(x - 1, y, dist + 1); vis[x - 1][y] = false;}
        if((map[x][y - 1] != ‘X‘) && !vis[x][y - 1]) {vis[x][y - 1] = true; dfs(x, y - 1, dist + 1); vis[x][y - 1] = false;}
        if((map[x][y + 1] != ‘X‘) && !vis[x][y + 1]) {vis[x][y + 1] = true; dfs(x, y + 1, dist + 1); vis[x][y + 1] = false;}
        if((map[x + 1][y] != ‘X‘) && !vis[x + 1][y]) {vis[x + 1][y] = true; dfs(x + 1, y, dist + 1); vis[x + 1][y] = false;}
    }
}

int main()
{
    while(scanf("%d%d%d%*c", &N, &M, &T) != EOF && N && M && T)
    {    
        int x, y, Wall = 0;
        ok = false;
        for(int i = 1; i <= M; i++)
            map[0][i] = map[N + 1][i] = ‘X‘, vis[0][i] = vis[N + 1][i] = true;
        for(int i = 1; i <= N; i++)
            map[i][0] = map[i][M + 1] = ‘X‘, vis[i][0] = vis[i][M + 1] = true;

        for(int i = 1; i <= N; i++)
        {
            for(int r = 1; r <= M; r++)
            {
                scanf("%c", &map[i][r]);
                if(map[i][r] == ‘S‘) 
                    x = i, y = r;
                if(map[i][r] == ‘D‘)
                    x_e = i, y_e = r;
                if(map[i][r] == ‘X‘)
                    Wall++;
                vis[i][r] = false;
            }
            scanf("%*c"); 
        }
        vis[x][y] = true;

        if(N * M - Wall >= T)
            dfs(x, y, 0);
        
        if(ok) printf("YES\n");
        else printf("NO\n");
    }
    return 0;
}