求大佬解惑！！！

同样是if反复判定 为什么两个思路一个倒着减回去只有60分 正着加上去的就满分了

60分版本如下

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double  s, v;
    cin >> s >> v;
    double t1 = s / v;
    int t = ceil(t1);
    int h = t / 60;
    int m = t % 60;
    int H,M;
    if(h<=7)
    {
        H=7-h;
        if (m >= 50 && m<=59)
        {
            h = h + 1;
            m = m - 50;
            M = 60 - m;
            printf("0%d:0%d", H, M);
        }
        else if(m>=60)
        {
            h = h + 1;
            m = m - 50;
            M = 60 - m;
            printf("0%d:%d", H, M);
        }
        else
        {
            M = 50 - m;
            printf("0%d:%d", H, M);
        }
    } 
    else
    {
        H=24-(h-7);
        if (m >= 50 && m<=59)
        {
            h = h + 1;
            m = m - 50;
            M = 60 - m;
            printf("%d:0%d", H, M);
        }
        else if(m>=60)
        {
            h = h + 1;
            m = m - 50;
            M = 60 - m;
            printf("%d:%d", H, M);
        }
        else
        {
            M = 50 - m;
            printf("%d:%d", H, M);
        }   
    }

    return 0;
}

100分版本如下

#include<iostream>
#include<cmath>
using namespace std;
int main()
{
    double s, v;
    cin >> s >> v;
    int T, t1,t2;
    T = 24 * 60 + 8 * 60;
    t1 = ceil(s / v) + 10;
    t2 = T - t1;
    int h, m;
    h = t2 / 60;
    m = t2 % 60;
    if (h >= 24)
    {
        h = h - 24;
        if (m >= 10)
        {
            printf("0%d:%d", h, m);
        }

        else
        {
            printf("0%d:0%d", h, m);
        }
    }
    else if (h < 10)
    {
        if (m >= 10)
        {
            printf("0%d:%d", h, m);
        }

        else
        {
            printf("0%d:0%d", h, m);
        }
    }
    else
    {
        if (m >= 10)
        {
            printf("%d:%d", h, m);
        }

        else
        {
            printf("%d:0%d", h, m);
        }
    }
    return 0;
}

感谢帮助！！！