Canadian Computing Competition 2010 Junior 5 Solution

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <fstream>
#include <string>

using namespace std;
int min(int x1, int x2) {
  if (x1 < x2) return x1;
  else return x2;
}

int main() {
  int board[8][8];
  int startx, starty;
  cin >> startx;
  cin >> starty;
  //The contest starts indexing at one, not zero
  startx -= 1;
  starty -= 1;
  for (int x = 0; x < 8; x++) {
    for (int y = 0; y < 8; y++) {
      board[x][y] = 999; //999 represents "unexplored by the program"
    }
  }
  board[startx][starty] = 0;
  int finalx, finaly;
  cin >> finalx;
  cin >> finaly;
  finalx -= 1;
  finaly -= 1;
  //We'll make 64 passes over the board, since no two squares can possibly be more than 64 squares apart (a path contradicting this must pass over the same square twice, making it suboptimal). Usually a mere 1-3 passes will suffice since cells explored during a pass will become usable for the rest of the pass (eg. the program can go 1,1 -> 3,2 -> 4,4 -> 6,5 in one pass)
  for (int t = 0; t < 64; t++) {
    for (int x = 0; x < 8; x++) {
      for (int y = 0; y < 8; y++) {
        //The basic trick here is that if a cell takes N moves to it, the cell 1 move away will take N+1 moves unless there is another, shorter path to it
        if (board[x][y] < 999) {
      if (x>1 && y>0) board[x-2][y-1] = min(board[x-2][y-1],board[x][y]+1);
      if (x>1 && y<7) board[x-2][y+1] = min(board[x-2][y+1],board[x][y]+1);
      if (x>0 && y>1) board[x-1][y-2] = min(board[x-1][y-2],board[x][y]+1);
      if (x>0 && y<6) board[x-1][y+2] = min(board[x-1][y+2],board[x][y]+1);
      if (x<7 && y>1) board[x+1][y-2] = min(board[x+1][y-2],board[x][y]+1);
      if (x<7 && y<6) board[x+1][y+2] = min(board[x+1][y+2],board[x][y]+1);
      if (x<6 && y>0) board[x+2][y-1] = min(board[x+2][y-1],board[x][y]+1);
      if (x<6 && y<7) board[x+2][y+1] = min(board[x+2][y+1],board[x][y]+1);
    }
      }
    }
    if (board[finalx][finaly] < 999) {
      cout << board[finalx][finaly] << "\n"; //We found it, report and abort
      return 0;
    }
  }
}