ABC001-D.cpp

#include "bits/stdc++.h"
using namespace std;
static const int inf = 1<<30;

int tl[24*13];


vector<int> split(const string &s, char delim) {
    vector<int> elems;
    string item;
    for (char ch: s) {
        if (ch == delim) {
            if (!item.empty())
                elems.push_back(atoi(item.c_str()));
            item.clear();
        }
        else {
            item += ch;
        }
    }
    if (!item.empty())
        elems.push_back(atoi(item.c_str()));
    return elems;
}
int TLtoTime(int _tl){
    int h=_tl/12;
    int m=_tl%12;
    return h*100+5*m;
}
int TimetoTL(int time,int md){
    if(md==1) time+=(5-(time%5))==5? 0:(5-(time%5)); else time-=time%5;
    int m = (time % 100)/5;
    int h = time /100;
    return h*12+m;
}

int main(void){
    int N;
    cin >> N;
    vector<int> v;
    for(int i=0;i<12*24+1;i++){
        tl[i]=0;
    }

    for(int i=0;i<N;i++){
        string str;
        cin >> str;
        v=split(str, '-');
        int b=TimetoTL(v[0],0);
        int e=TimetoTL(v[1],1);
        tl[b]+=1;
        tl[e]+=-1;
    }
    for(int i=0;i<12*24+1;i++){
        if(i==0) continue;
        tl[i]=tl[i]+tl[i-1];
    }

    bool check=false;
    for(int i=0;i<12*24+1;i++){
        if(tl[i]>=1 && !check){cout << setw(4) << setfill('0')<< TLtoTime(i)<<"-"; check=true;}
        if(tl[i]==0 && check) {cout << setw(4) << setfill('0')<<TLtoTime(i)<<endl; check=false;}
    }
    return 0;
}