Jamie and Alarm Snooze
Hazrat Ali
A time is considered lucky if it contains a digit '7'. For example, 13: 07 and 17: 27 are lucky, while 00: 48 and 21: 34 are not lucky.
Note that it is not necessary that the time set for the alarm and the wake-up time are on the same day. It is guaranteed that there is a lucky time Jamie can set so that he can wake at hh: mm.
Formally, find the smallest possible non-negative integer y such that the time representation of the time x·y minutes before hh: mm contains the digit '7'.
Jamie uses 24-hours clock, so after 23: 59 comes 00: 00.
The first line contains a single integer x (1 ≤ x ≤ 60).
The second line contains two two-digit integers, hh and mm (00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59).
Print the minimum number of times he needs to press the button.
3
11 23
2
5
01 07
0
Solution
#include <bits/stdc++.h>
using namespace std;
int main()
{
int x;
cin >> x;
int h, m;
cin >> h >> m;
int ans = 0;
while (h % 10 != 7 and m % 10 != 7)
{
if (m < x)
{
m = (m + 60 - x) % 60;
h = (h == 0) ? 23 : h - 1;
}
else
{
m -= x;
}
ans++;
}
cout << ans << endl;
return 0;
}