1697.cpp

#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;

int n, k;
bool visit[100001];

void bfs(int a)
{
    queue<pair<int, int>> q;
    q.push(make_pair(a, 0));

    while (!q.empty())
    {
        int x = q.front().first;
        int cnt = q.front().second;
        q.pop();

        if (x == k)
        {
            cout << cnt;
            break;
        }
        if (x + 1 >= 0 && x + 1 < 100001)
        {
            if (!visit[x + 1])
            {
                visit[x + 1] = true;
                q.push(make_pair(x + 1, cnt + 1));
            }
        }
        if (x - 1 >= 0 && x - 1 < 100001)
        {
            if (!visit[x - 1])
            {
                visit[x - 1] = true;
                q.push(make_pair(x - 1, cnt + 1));
            }
        }
        if (2 * x >= 0 && 2 * x < 100001)
        {
            if (!visit[2 * x])
            {
                visit[2 * x] = true;
                q.push(make_pair(2 * x, cnt + 1));
            }
        }
    }
}

int main()
{

    cin >> n >> k;
    visit[n] = true;
    bfs(n);
    return 0;
}