HDOJ 1010

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<iomanip>
#include<cfloat>
using namespace std;
bool  flag;
char a[10][10];
int n, m, t, di, dj;
int c[4][2] = { { 1,0 },{ 0,1 },{ 0,-1 },{ -1,0 } };
void keng(int x,int y,int s) {
int i;
if (flag) {
return;
}
if (a[x][y] == 'X') {
return;
}
if (x == di&&y == dj&&s == t) {
flag = 1;
return;
}
if (x < 0 || x >= n || y < 0 || y >= m) {
return;
}
for (i = 0;i < 4;i++) {
a[x][y] = 'X';
keng(x + c[i][0], y + c[i][1], s + 1);
if (flag)
return;
a[x][y] = '.';
}
}
int main()
{

while ((scanf("%d%d%d",&n,&m,&t))&& (n || m || t)) {
getchar();
int si, sj, k = 0;
flag = 0;
for (int i = 0;i < n;i++) {

for (int j = 0;j < m;j++) {
scanf("%c", &a[i][j]);
if (a[i][j] == 'S') {
si = i;
sj = j;
}
else if (a[i][j] == 'X') {
k++;
}
else if (a[i][j] == 'D') {
di = i;
dj = j;
}
}
getchar();
}
if (n*m - k < t) {
cout << "NO" << endl;
}
else if ((si + sj + di + dj + t) % 2 == 1) {
cout << "NO" << endl;
}
else {
keng(si, sj, 0);
if (flag)
cout << "YES" << endl;
else
cout << "NO" << endl;
}

}

return 0;
}