poj2488

简单跳马搜索

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxn 26

struct Point
{
    int x, y;
} way[maxn * maxn];

bool map[maxn][maxn];
int p, q;
bool found;
int dir[8][2] =
{
{ -2, -1 },
{ -2, 1 },
{ -1, -2 },
{ -1, 2 },
{ 1, -2 },
{ 1, 2 },
{ 2, -1 },
{ 2, 1 } };

bool ok(int x, int y)
{
    if (x < 0 || y < 0 || x >= q || y >= p)
        return false;
    if (map[x][y])
        return false;
    return true;
}

void dfs(int x, int y, int step)
{
    way[step].x = x;
    way[step].y = y;
    if (step == p * q - 1)
    {
        found = true;
        return;
    }
    for (int i = 0; i < 8; i++)
        if (ok(x + dir[i][0], y + dir[i][1]))
        {
            map[x + dir[i][0]][y + dir[i][1]] = true;
            dfs(x + dir[i][0], y + dir[i][1], step + 1);
            if (found)
                return;
            map[x + dir[i][0]][y + dir[i][1]] = false;
        }
}

void print()
{
    for (int i = 0; i < p * q; i++)
        printf("%c%d", way[i].x + 'A', way[i].y + 1);
    printf("\n\n");
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    int s = 0;
    while (t--)
    {
        s++;
        printf("Scenario #%d:\n", s);
        memset(map, 0, sizeof(map));
        scanf("%d%d", &p, &q);
        for (int i = 0; i < q; i++)
        {
            for (int j = 0; j < p; j++)
            {
                found = false;
                map[i][j] = true;
                dfs(i, j, 0);
                if (found)
                    break;
                map[i][j] = false;
            }
            if (found)
                break;
        }
        if (found)
            print();
        else
            printf("impossible\n\n");
    }
    return 0;
}