POJ 2488 A Knight's Journey

把起点设为A 1点，DFS找序列

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int r,c,flag,map[30][30];
int lc[1000][2];
int dir[8][2]={{-1,-2},{1,-2},{-2,-1},{2,-1},
               {-2,1},{2,1},{-1,2},{1,2}};
bool judge(int x,int y)
{
    if (x <= 0 || x > r || y <= 0 || y > c)
        return false;
    if (map[x][y] == 1)
        return false;
    return true;
}
void dfs(int x,int y,int cnt)
{
    int tx,ty,i;
    map[x][y]=1;
    lc[cnt][0]=x;
    lc[cnt][1]=y;
    if (cnt+1 == r*c)
    {
        for (i=0; i<=cnt; i++)
            printf("%c%d",lc[i][1]-1+'A',lc[i][0]);
        printf("\n\n");
        flag=1;
        return ;
    }
    for (i=0; i<8; i++)
    {
        tx=x+dir[i][0];
        ty=y+dir[i][1];
        if (judge(tx,ty))
        {
            dfs(tx,ty,cnt+1);
            if (flag == 1)
                break;
        }
    }
    map[x][y]=0;
}
int main()
{
    int i,T,prob;
    scanf("%d",&T);
    prob=1;
    while (T--)
    {
        scanf("%d%d",&r,&c);
        flag=0;
        memset(map,0,sizeof(map));
        printf("Scenario #%d:\n",prob);
        dfs(1,1,0);
        prob++;
        if (flag == 0)
            printf("impossible\n\n");
    }
}