Pog.org 2488

/*
* Poj 2488
* It is good to traverse DFS, record the path that has passed, as long as you walk through the p * q square without repeating (end condition)
*/

# Include <iostream>
# Include <cstdio>
# Include <cstring>
Using namespace STD;
Const int max = 30;
Int Kase;
Int p, q;
Int vis [Max] [Max]; // mark the Array
// Direction array, just in the Lexicographic Order
Int dir [8] [2] = {-1,-2}, {1,-2}, {-2,-1}, {2,-1 }, {-2, 1}, {2, 1}, {-1, 2}, {1, 2}; // eight directions
Int path [Max * max] [2]; // used to record the path passed by DFS
Int flag;

Void DFS (int x, int y, int step)
{

If (step = p * q) // The p * q is finished.
{
Cout <"Scenario #" <++ Kase <":" <Endl;
For (INT I = 0; I <p * q; I ++)
{
Printf ("% C % d", path [I] [1] + 'A', path [I] [0] + 1 ); // note that the subscript of the recorded path starts from 0. According to my design, output the Y value first.
}
Cout <Endl;
Flag = 1;
Return;
}


For (int d = 0; D <8; D ++)
{
Int NX, NY; // only local variables can be made.
Nx = x + dir [d] [0];
NY = Y + dir [d] [1];
If (! Vis [NX] [NY] & NX> = 0 & NX <P & ny> = 0 & ny <q)
{
Vis [NX] [NY] = 1;
Path [STEP] [0] = NX;
Path [STEP] [1] = NY;
DFS (NX, NY, step + 1 );
Vis [NX] [NY] = 0; // unmark
If (FLAG)
Return;
}
}
}


Int main ()
{
Int T;
While (scanf ("% d", & T )! = EOF)
{
Kase = 0;
While (t --)
{
Flag = 0;
Memset (VIS, 0, sizeof (VIS ));
Scanf ("% d", & P, & Q );
Path [0] [0] = 0;
Path [0] [1] = 0;
Vis [0] [0] = 1;
DFS (0, 0, 1 );

If (! Flag)
{
Cout <"Scenario #" <++ Kase <":" <Endl;
Cout <"impossible" <Endl;
}
}
}
Return 0;
}


/*
Pay attention to the following issues:
1. Chess stands for letters and numbers.
2. It is output in Lexicographic Order, so pay attention to the search direction! This is a pitfall.
3. Ignore the phrase "the knight can start and end on any square of the board .".
It's a pitfall. In fact, you only need to start searching from Point A1. As long as you can start searching from point A1.
From any point on the Board as the starting point, you can find a path to traverse the board, and the question
It is required to output data in Lexicographic Order, so you only need to start searching from the start point!
*/