不保证是题解

#include<iostream>
#include<queue>
using namespace std;
using ll = int;
using FLOAT = bool;
FLOAT vis[100001];
ll n,k,a[3]{1,-1};
void bfs(){
    queue<ll>q,t;
    q.push(n);t.push(0);
    while(!q.empty()){
        a[2] = q.front();
        for(int i{0};i < 3;i++){
            if(q.back()==k)cout << t.back(),exit(0);
            if(a[2]+a[i] >= 0 && a[2]+a[i] <= 100000 && !vis[a[2]+a[i]]){
                q.push(a[2]+a[i]);t.push(t.front()+1);
                vis[q.back()] = true;
            }
        }
        q.pop();t.pop();
    }
    return;
}
int main(){
    cin >> n >> k;
    bfs();
    return 0;
}