问题标题: 酷町堂：5014国际象棋

TLE90：

#include <iostream>

using namespace std;

int sx, sy, fx, fy;
int vis[10][10], G[10][10];
const int dir[8][2] = {
    {-1, 0}, {-1, 1}, {0, 1}, {1, 1},
    {1, 0}, {1, -1}, {0, -1}, {-1, -1}
};
int out[10005][3], total;

bool valid(int x, int y) {
    if(x >= 1 && x <= 8 && y >= 1 && y <= 8) return true;
    return false;
}

void print(int n) {
    for(int i=1; i<=n; i++) {
        if(i != n)
            cout << "(" << out[i][1] << "," << out[i][2] << ")" << "->";
        else
            cout << "(" << out[i][1] << "," << out[i][2] << ")";
    }
    cout << endl;
}

void dfs(int x, int y, int num) {
    // cout << x << " " << y << endl;
    out[num][1] = x;
    out[num][2] = y;
    if(x == fx && y == fy) {
        total ++;
        if(total <= 5)
            print(num);
    }
    for(int i=0; i<8; i++) {
        int nx = x + dir[i][0], ny = y + dir[i][1];
        if(valid(nx, ny) && vis[nx][ny] == 0 && G[nx][ny] == 0) {
            vis[nx][ny] = 1;
            dfs(nx, ny, num + 1);
            vis[nx][ny] = 0;
        }
    }
}

int main() {
    cin >> sx >> sy >> fx >> fy;
    for(int i=1; i<=8; i++)
        for(int j=1; j<=8; j++)
            cin >> G[i][j];
    vis[sx][sy] = 1;
    dfs(sx, sy, 1);
    cout << total;
    return 0;
}