题解 | 计时相当于60进制减法

#include<stdio.h>
int main() {
    int h1, m1, h2, m2;
    float s1, s2;
    scanf("%d:%d:%f%d:%d:%f", &h1, &m1, &s1, &h2, &m2, &s2);
    int h3 = h2 - h1;
    int m3 = m2 - m1;
    float s3 = s2 - s1;
    if (s3 < 0) {
        m3--;
        s3 += 60;
    }
    if (m3 < 0) {
        h3--;
        m3 += 60;
    }
    printf("%02d:%02d:%06.3f", h3, m3, s3);
    return 0;
}