uva 439 - Knight Moves

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

int vis[10][10], ans[100];;
int step[10][3]= {{1,2},{1,-2},{-1,2},{-1,-2},{2,1},{-2,1},{2,-1},{-2,-1}};
int bfs(int x1, int y1, int x2, int y2)
{
int front = 0, rear = 1, list[100][3];
list[front][0] = x1;
list[front][1] = y1;
vis[x1][y1] = 1;
ans[front] = 0;
while(front < rear)
{
for(int i = 0; i < 8; i++)
{
int x = step[i][0] + list[front][0], y = step[i][1] + list[front][1];
if(x>0 && x<=8 && y>0 && y<=8 && !vis[x][y])
{
if(x == x2 && y == y2) return ans[front]+1;
list[rear][0] = x;
list[rear][1] = y;
ans[rear++] = ans[front] + 1;
vis[x][y] = 1;
}
}
front++;
}
return 0;
}
int main()
{
char s1[3], s2[3];
while(cin >> s1 >> s2)
{
memset(vis, 0, sizeof(vis));
memset(ans, 0, sizeof(ans));
int count = bfs(s1[1]-'0', s1[0]-'a'+1, s2[1]-'0', s2[0]-'a'+1);
printf("To get from %s to %s takes %d knight moves.\n", s1, s2, count );
}
return 0;
}