[백준 1697] 숨바꼭질 (BFS) (C/C++)

#include <stdio.h>
#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
 
int start, arrive;
int visited[100010];
 
queue<int> q;
 
void BFS()
{
    visited[start] = 1;
    q.push(start);
    
    while(!q.empty())
    {
        int x = q.front();
        q.pop();
        
        for(int i = 1; i <= 3; i++)
        {
            int xpos;
            
            if(i == 1)
            {
                xpos = x - 1;    
            }
            else if(i == 2)
            {
                xpos = x + 1;
            }
            else if(i == 3)
            {
                xpos = x * 2;
            }
            
            if(xpos >= 0 && xpos <= 100000 && visited[xpos] == 0)
            {
                visited[xpos] = visited[x] + 1;
                q.push(xpos);
            }
            
            if(xpos == arrive)
            {
                return;
            }
        }
    }
}
 
int main(void)
{
//    freopen("B1697_input.txt", "r", stdin);
    
    cin >> start >> arrive;
    
    BFS();
    
    cout << visited[arrive]-1;
        
    return 0;
}