[프로그래머스 C++] 호텔 대실

#include <string>
#include <vector>
#include <queue>
#include <algorithm>
#include <iostream>
 
using namespace std;
 
int solution(vector<vector<string>> book_time) {
    int answer = 0;
    
    // 0부터 :직전까지 담아서 * 100, :다음부터 끝날때까지 담아서
    
    vector<pair<int, int>> v;
    priority_queue<int, vector<int>, greater<>> pq;
    
    for (int i=0; i<book_time.size(); i++)
    {
        int start, end;
        string in = book_time[i][0];
        for (int j=0; j<in.size(); j++)
        {
            if (in[j] == ':')
            {
                const int inHour = stoi(in.substr(0, j)) * 100;
                const int inMinute = stoi(in.substr(j+1));
                start = inHour + inMinute;
            }
        }
        
        string out = book_time[i][1];
        for (int j=0; j<out.size(); j++)
        {
            if (out[j] == ':')
            {
                int outHour = stoi(out.substr(0, j)) * 100;
                int outMinute = stoi(out.substr(j+1)) + 10;
                outHour += (outMinute / 60) * 100;
                outMinute = outMinute % 60;
                
                end = outHour + outMinute;
            }
        }
        
        v.push_back({start, end});
    }
    
    ::sort(v.begin(), v.end(), [](const pair<int, int>& A, const pair<int, int>& B){ return A.first < B.first; });
    // 1410 1420 1500 1640 1820
    
    int cnt = 0;
    for (int i=0; i<v.size(); i++)
    {
        if (pq.empty() || v[i].first < pq.top())
        { // 객실 추가
            cnt++;
            pq.push(v[i].second);
        }
        else
        { // 이전 객실 사용
            pq.pop();
            pq.push(v[i].second);
        }
    }
    
    return answer = cnt;
}