ayit第十四周训练a题

Background
The knight is getting bored of seeing the same black and white squares again and again and has decided to make a journey
around the world. Whenever a knight moves, it is two squares in one direction and one square perpendicular to this. The world of a knight is the chessboard he is living on. Our knight lives on a chessboard that has a smaller area than a regular 8 * 8 board, but it is still rectangular. Can you help this adventurous knight to make travel plans?

Problem
Find a path such that the knight visits every square once. The knight can start and end on any square of the board.

Input

The input begins with a positive integer n in the first line. The following lines contain n test cases. Each test case consists of a single line with two positive integers p and q, such that 1 <= p * q <= 26. This represents a p * q chessboard, where p describes how many different square numbers 1, . . . , p exist, q describes how many different square letters exist. These are the first q letters of the Latin alphabet: A, . . .

Output

The output for every scenario begins with a line containing "Scenario #i:", where i is the number of the scenario starting at 1. Then print a single line containing the lexicographically first path that visits all squares of the chessboard with knight moves followed by an empty line. The path should be given on a single line by concatenating the names of the visited squares. Each square name consists of a capital letter followed by a number.
If no such path exist, you should output impossible on a single line.

Sample Input

3
1 1
2 3
4 3

Sample Output

Scenario #1:
A1

Scenario #2:
impossible

Scenario #3:
A1B3C1A2B4C2A3B1C3A4B2C4

 

#include
#include
int book[110][110],n,m,ss,e[110],f[110],w;
int next[8][2]={-2,-1, -2,1, -1,-2,-1,2,1,-2,1,2,2,-1,2,1};
void dfs(int x,int y,int step)
{
    e[step]=x;
    f[step]=y;
    int i,tx,ty;
    if(step==n*m)
    {
        ss=1;
        return;
    }
    for(i=0;i<8;i++)
    {
        tx=x+next[i][0];
        ty=y+next[i][1];
        if(tx>=0&&tx=0&&ty

 

题意  给出一个p行q列的国际棋盘，马可以从任意一个格子开始走，问马能否不重复的走完所有的棋盘。如果可以，输出按字典序排            列最小的路径。输出时，列用大写字母表示，行用阿拉伯数字表示，先输出列，再输出行。

思路    先选择一个固定坐标，题目要求输出路径字典序最小，选择(1,1)也就是作为起点开始搜索；注意移动方向！纵坐标                 从 左到右，纵坐标一样就横坐标从上到下，这样去规定方向数组dx[]和dy[];

题型  深搜