一、y总sscanf

#include<bits/stdc++.h>
using namespace std;
int get_seconds(int h, int m, int s) {
    return h * 3600 + m * 60 + s;
}
int get_time() {
    string line;
    getline(cin, line);

    if (line.back() != ')')
        line += "(+0)";
    int h1, m1, s1, h2, m2, s2, d;
    sscanf(line.c_str(), "%d:%d:%d %d:%d:%d (+%d)", &h1, &m1, &s1, &h2, &m2, &s2, &d);

    return get_seconds(h2, m2, s2) - get_seconds(h1, m1, s1)+d*24*3600;


}
int main() {

    int n;
    cin >> n;
    string line;
    getline(cin, line);
    while (n--) {
        int time = (get_time() + get_time()) / 2;
        int hour = time / 3600, minute = time % 3600 / 60, second = time % 60;
        printf("%02d:%02d:%02d\n", hour, minute, second);
    }

    return 0;
}

二、自己写的

#include<bits/stdc++.h>
using namespace std;
int flyh, flym, flys;
void count_time(int h1, int m1, int s1, int h2, int m2, int s2) {
    if (s2 >= s1) {
        flys = s2 - s1;
    }
    else {
        m2--;
        flys = s2 + 60 - s1;
    }
    if (m2 >= m1) {
        flym = m2 - m1;
    }
    else {
        h2--;
        flym = m2 + 60 - m1;
    }
    flyh = h2 - h1;

}
int main()
{
    int q;
    cin >> q;
    while (q--) {
        flyh = 0; flym = 0; flys = 0;
        int h1, m1, s1, h2, m2, s2, day1=0;
        int h3, m3, s3, h4, m4, s4, day2=0;
        scanf("%d:%d:%d %d:%d:%d (+%d)", &h1, &m1, &s1, &h2, &m2, &s2, &day1);
        scanf("%d:%d:%d %d:%d:%d (+%d)", &h3, &m3, &s3, &h4, &m4, &s4, &day2);
        //cout<<h1<<' '<<m1<<' '<<s1<<' '<<h2<<' '<<m2<<' '<<s2<<' '<<day1<<endl;

        int nowh = 0, nowm = 0, nows = 0;
        if(day1==2){
            count_time(h1,m1,s1,24,0,0);
            nowh+=flyh,nowm+=flym,nows+=flys;
            nowh+=24;
            count_time(0,0,0,h2,m2,s2);
            nowh+=flyh,nowm+=flym,nows+=flys;


        }
        else  if(day1==1){

            count_time(h1,m1,s1,24,0,0);
            nowh+=flyh,nowm+=flym,nows+=flys;
            count_time(0,0,0,h2,m2,s2);
            nowh+=flyh,nowm+=flym,nows+=flys;

        }
        else {
        count_time(h1, m1, s1, h2, m2, s2);
        //cout << flyh << ' ' << flym << ' ' << flys << endl;
        nowh += flyh, nowm += flym, nows += flys;

        }
        if(day2==2){
            count_time(h3,m3,s3,24,0,0);
            nowh+=flyh,nowm+=flym,nows+=flys;
            nowh+=24;
            count_time(0,0,0,h4,m4,s4);
            nowh+=flyh,nowm+=flym,nows+=flys;


        }
       else  if(day2==1){
            count_time(h3,m3,s3,24,0,0);
            nowh+=flyh,nowm+=flym,nows+=flys;
            count_time(0,0,0,h4,m4,s4);
            nowh+=flyh,nowm+=flym,nows+=flys;


        }
        else{
            count_time(h3, m3, s3, h4, m4, s4);
            nowh += flyh, nowm += flym, nows += flys;
        }

        int sum = nowh * 3600 + nowm * 60 + nows;
        sum /= 2;

        nowh = sum / 3600;
        nowm = (sum - nowh * 3600) /60;
        nows = (sum - nowh * 3600 - nowm * 60);

        printf("%02d:%02d:%02d\n", nowh, nowm, nows);



    }
    return 0;
}