ACM篇 ： POJ 1321 -- 棋盘问题

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int MAX = 8;
bool board[MAX+1][MAX+1];
bool occu[MAX+1];
int n;
int k;
int ans;
int readchar()
{
int t;
while (t = getchar())
{
if (t == '.' || t == '#')
break;

}
return t;
}

void _init()
{
memset(board, 0, sizeof(board));
memset(occu, 0, sizeof(occu));
}
void read_board()
{
for (int i = 1; i <= n; i++)
for (int j = 1; j <= n; j++)
board[i][j] = (readchar() == '#')  ? true : false;
}

void _dfs(int row, int laid)
{
if (laid == k)
{
ans++;
return;
}
if (row > n)
return;

for (int j = 1; j <= n; j++)
{
if (board[row][j] && !occu[j])
{
occu[j] = true;
_dfs(row+1, laid+1);
occu[j] = false;
}
}
_dfs(row+1, laid);
}
int main()
{
while (scanf("%d%d", &n, &k) && n != -1 && k != -1)
{
_init();
read_board();

ans = 0;
_dfs(1, 0);

printf("%d\n", ans);
}
return 0;
}