[C++] 16953 - A → B

문제 링크 : https://www.acmicpc.net/problem/16953

16953번: A → B

 

 

 

#include<bits/stdc++.h>
 
#define endl '\n'
 
using namespace std;
 
typedef pair<int, int> pii;
 
int A, B;
 
int BFS()
{
    pii p;
    queue<pii> Q;
    Q.push(pii(B, 1));
 
    while(!Q.empty())
    {
        p = Q.front();
        Q.pop();
        if(p.first == A)
            return p.second;
        if(p.first == 0)
            continue;
        if(p.first%10 == 1)
            Q.push(pii(p.first/10, p.second+1));
        if(p.first%2 == 0)
            Q.push(pii(p.first/2, p.second+1));
    }
 
    return -1;
}
 
int main()
{
    cin >> A >> B;
 
    cout << BFS() << endl;
 
 
    return 0;
}