셔틀버스 C++

https://programmers.co.kr/learn/courses/30/lessons/17678

코딩테스트 연습 - [1차] 셔틀버스

#include <string>
#include <vector>
#include <algorithm>
#include <iostream>

using namespace std;
vector<int> tm;

string solution(int n, int t, int m, vector<string> timetable) {
    string answer = "";
    
    for(int i=0; i<timetable.size(); i++){
        int hour = stoi(timetable[i].substr(0,2)) * 60;
        int min = stoi(timetable[i].substr(3,2));
        tm.push_back(hour+min);
    }
    
    sort(tm.begin(),tm.end());
    
    int curtime = 9*60;
    int index = 0;
    int ans = 0;
    for(int i=0; i<n; i++){
        int j=0;
        for(; j<m && index < tm.size(); j++){
            if(tm[index] <= curtime){
                index++;
            }
            else{
                break;
            }
        }
        
        if(i == n-1){
            if(j==m){
                ans = tm[index-1]-1;
            }
            else
                ans = curtime;
        }
        else    curtime += t;
    }
    
    string tmp = "";
    int hour = ans/60;
    if(hour <10)    tmp +="0"+to_string(hour);
    else    tmp+=to_string(hour);
    
    tmp +=":";
    int min = ans%60;
    if(min<10)  tmp += "0" + to_string(min);
    else    tmp+= to_string(min);
    
    answer = tmp;
    return answer;
}