递归系列-----------八皇后解法

#include <stdio.h>

#define N 8

typedef struct _tag_Pos
{
int ios;
int jos;
} Pos;

static char board[N+2][N+2];
static Pos pos[] = { {-1, -1}, {-1, 0}, {-1, 1} };
static int count = 0;

void init()
{
int i = 0;
int j = 0;

for(i=0; i<N+2; i++)
{
board[0][i] = '#';
board[N+1][i] = '#';
board[i][0] = '#';
board[i][N+1] = '#';
}

for(i=1; i<=N; i++)
{
for(j=1; j<=N; j++)
{
board[i][j] = ' ';
}
}
}

void display()
{
int i = 0;
int j = 1;

for(i=0; i<N+2; i++)
{
for(j=0; j<N+2; j++)
{
printf("%c", board[i][j]);
}

printf("\n");
}
}

int check(int i, int j)
{
int ret = 1;
int p = 0;

for(p=0; p<3; p++)
{
int ni = i;
int nj = j;

while( ret && (board[ni][nj] != '#') )
{
ni = ni + pos[p].ios;
nj = nj + pos[p].jos;

ret = ret && (board[ni][nj] != '*');
}
}

return ret;
}

void find(int i)
{
int j = 0;

if( i > N )
{
count++;

printf("Solution: %d\n", count);

display();

getchar();
}
else
{
for(j=1; j<=N; j++)
{
if( check(i, j) )
{
board[i][j] = '*';

find(i+1);

board[i][j] = ' ';
}
}
}
}

int main()
{
init();
find(1);

return 0;
}