1 #include<iostream>
 2 #include<cmath>
 3 
 4 using namespace std;
 5 
 6 int main() {
 7     int last = 0, now = 0;
 8     float run = 0.0;
 9     int s = 0, m = 0, h = 0;
10     cin >> last >> now;
11     run = (now * 1.0 - last) / 100.0;    //注意整型转化为浮点型
12     h = run / 3600;
13     m = (run - (h * 3600)) / 60;
14     s = round(run - (h * 3600) - (m * 60));    //利用round进行四舍五入
15 
16     if (s == 60) {                            //进位
17         m++;
18         s = 0;
19     }
20     printf("%02d:%02d:%02d", h, m, s);
21     return 0;
22 }