[백준 7562] 나이트의 이동 (BFS) (C/C++)

#include <stdio.h>
#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
 
int map[310][310];
int T;
int len;
int startX, startY, endX, endY;
 
queue<pair<int, int>> q;
int visited[310][310];
 
int dx[8] = {-1, -2, -2, -1, 1, 2, 2, 1};
int dy[8] = {-2, -1, 1, 2, 2, 1, -1, -2};
 
void init()
{
    for(int i = 0; i < len; i++)
    {
        for(int j = 0; j < len; j++)
        {
            visited[i][j] = 0;
        }
    }
}
 
int safe(int x, int y)
{
    if(x >= 0 && x < len && y >= 0 && y < len)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}
 
void BFS()
{
    visited[startX][startY] = 1;
    q.push({startX, startY});
    
    while(!q.empty())
    {
        int x = q.front().first;
        int y = q.front().second;
        q.pop();
        
        for(int i = 0; i < 8; i++)
        {
            int xpos = x+dx[i];
            int ypos = y+dy[i];
            
            if(safe(xpos, ypos) == 1 && visited[xpos][ypos] == 0)
            {
                visited[xpos][ypos] = visited[x][y] + 1;
                q.push({xpos, ypos});
            }
        }
    }
}
 
int main(void)
{
//    freopen("B7562_input.txt", "r", stdin);
    
    scanf("%d", &T);
    
    for(int n = 1; n <= T; n++)
    {            
        cin >> len;
        cin >> startX >> startY >> endX >> endY;
        
        BFS();
        
        cout << visited[endX][endY]-1 << endl;
        
        init();
    }
        
    return 0;
}