17071. 숨바꼭질 5

문제링크 : https://www.acmicpc.net/problem/17071

#include <iostream>
#include <queue>
using namespace std;
bool visited[2][500001] = { false }; // 홀수번째 짝수번째 따로(진동 가능)
int main(void) {
    int startC;
    int startB;
    cin >> startB >> startC;
    queue<int> myQ;
    myQ.push(startB);
    visited[0][startB] = true;
    int turn = 1;
    if (startC == startB) {
        cout << "0";
        return 0;
    }
    while (!myQ.empty()) {
        startC += turn;
        if (startC > 500000) {
            cout << "-1";
            return 0;
        }
        if (visited[turn % 2][startC]) {
            cout << turn;
            return 0;
        }
        int size = myQ.size();
        for (int i = 0; i < size; i++) {
            int temp = myQ.front();
            myQ.pop();
            if (temp + 1 == startC || temp - 1 == startC || temp * 2 == startC) {
                cout << turn;
                return 0;
            }
            else {
                if (temp + 1 <= 500000 && !visited[turn % 2][temp + 1]) {
                    myQ.push(temp + 1);
                    visited[turn % 2][temp + 1] = true;
                }
                if (temp - 1 >= 0 && !visited[turn % 2][temp - 1]) {
                    myQ.push(temp - 1);
                    visited[turn % 2][temp - 1] = true;
                }
                if (temp * 2 <= 500000 && !visited[turn % 2][temp * 2]) {
                    myQ.push(temp * 2);
                    visited[turn % 2][temp * 2] = true;
                }
            }
        }
        turn++;
    }
    cout << "-1";
    return 0;
}