백준 1021번: 회전하는 큐

https://www.acmicpc.net/problem/1021

1021번: 회전하는 큐

 

#include<iostream>
#include<deque>
 
using namespace std;
 
 
 
int main(void)
{
    int N, M;
    cin >> N >> M;
    int ans = 0;
    deque<int> dq;
    for (int i = 1; i <= N; ++i)
    {
        dq.push_back(i);
    }
 
    for (int i = 0; i < M; ++i)
    {
        int num = 0;
        cin >> num;
        if (num == dq.front())
        { 
            dq.pop_front();
            continue;
        }
 
        auto iter1 = dq.begin(), iter2 =--dq.end();
        int leftcount = 1, rightcount = 0;
        while (*iter1 != num) 
        {
            ++iter1;
            ++rightcount;
        }
        while (*iter2 != num)
        {
            --iter2;
            ++leftcount;
        }
        if (rightcount > leftcount)
        {
            // 역방향
            while (dq.front() != num)
            {
                int number = dq.back();
                dq.pop_back();
                dq.push_front(number);
                ++ans;
            }
        }
        else
        {
            // 정방향
            while (dq.front() != num)
            {
                int number = dq.front();
                dq.pop_front();
                dq.push_back(number);
                ++ans;
            }
        }
        
        dq.pop_front();
    }
    cout << ans;
    return 0;
}