13549 숨바꼭질 3

13549 숨바꼭질 3

+1, -1 하는 경우와 *2 하는 경우를 나눠서 갱신해주면 된다.

#include <iostream>
#include <queue>
#define P pair<int,int>
using namespace std;
 
int visited[100001];
int n, k;
int dx[] = {1,-1};
 
void bfs() {
    queue<int> q;
    q.push(n);
    visited[n] = 1;
 
    int next;
    while (!q.empty()) {
        int cur = q.front();
        q.pop();
 
        for (int i = 0; i < 2; i++) {
            next = cur + dx[i];
            if (next < 0 || next > 100000) continue;
 
            if (visited[next] == 0 || visited[next] > visited[cur] + 1) {
                q.push(next);
                visited[next] = visited[cur] + 1;
            }
        }
 
        next = cur* 2;
        if (next < 0 || next > 100000) continue;
        if (visited[next] == 0 || visited[next] > visited[cur]) {
            q.push(next);
            visited[next] = visited[cur];
        }
    }
    cout << visited[k] - 1 << endl;
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin >> n >> k;
 
    bfs();
 
    return 0;
}