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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. int n, k, cnt[200004], visited[200004];
  4. vector<int> v;
  5. int main(){
  6.     cin >> n >> k;
  7.     visited[n] = 1;
  8.     queue<int> q;
  9.     q.push(n);
  10.  
  11.     while(q.size()){
  12.         int here = q.front();
  13.         q.pop();
  14.         for(int next : {here + 1, here - 1, here * 2}){
  15.             if(next >= 0 && next <= 200000){
  16.                 if(!visited[next]){
  17.                     q.push(next);
  18.                     visited[next] = visited[here] + 1;
  19.                     cnt[next] = here;
  20.                 }                
  21.             }
  22.         }
  23.     }
  24.  
  25.     for(int i = k; i != n; i = cnt[i]){
  26.         v.push_back(i);
  27.     }
  28.     cout << visited[k] - 1 << '\n';
  29.     for(int a : v){
  30.         cout << a << ' ';
  31.     }
  32. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin
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5 17
stdout
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4
17 16 8 4
https://ideone.com/1jW37l
language:
C++ (gcc 8.3)
created:
8 hours ago
visibility:
public

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