comments | difficulty | edit_url | rating | source | tags | ||
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true |
Medium |
1498 |
Weekly Contest 246 Q2 |
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You are participating in an online chess tournament. There is a chess round that starts every 15
minutes. The first round of the day starts at 00:00
, and after every 15
minutes, a new round starts.
- For example, the second round starts at
00:15
, the fourth round starts at00:45
, and the seventh round starts at01:30
.
You are given two strings loginTime
and logoutTime
where:
loginTime
is the time you will login to the game, andlogoutTime
is the time you will logout from the game.
If logoutTime
is earlier than loginTime
, this means you have played from loginTime
to midnight and from midnight to logoutTime
.
Return the number of full chess rounds you have played in the tournament.
Note: All the given times follow the 24-hour clock. That means the first round of the day starts at 00:00
and the last round of the day starts at 23:45
.
Example 1:
Input: loginTime = "09:31", logoutTime = "10:14" Output: 1 Explanation: You played one full round from 09:45 to 10:00. You did not play the full round from 09:30 to 09:45 because you logged in at 09:31 after it began. You did not play the full round from 10:00 to 10:15 because you logged out at 10:14 before it ended.
Example 2:
Input: loginTime = "21:30", logoutTime = "03:00" Output: 22 Explanation: You played 10 full rounds from 21:30 to 00:00 and 12 full rounds from 00:00 to 03:00. 10 + 12 = 22.
Constraints:
loginTime
andlogoutTime
are in the formathh:mm
.00 <= hh <= 23
00 <= mm <= 59
loginTime
andlogoutTime
are not equal.
We can convert the input strings to minutes
Then we round
The time complexity is
class Solution:
def numberOfRounds(self, loginTime: str, logoutTime: str) -> int:
def f(s: str) -> int:
return int(s[:2]) * 60 + int(s[3:])
a, b = f(loginTime), f(logoutTime)
if a > b:
b += 1440
a, b = (a + 14) // 15, b // 15
return max(0, b - a)
class Solution {
public int numberOfRounds(String loginTime, String logoutTime) {
int a = f(loginTime), b = f(logoutTime);
if (a > b) {
b += 1440;
}
return Math.max(0, b / 15 - (a + 14) / 15);
}
private int f(String s) {
int h = Integer.parseInt(s.substring(0, 2));
int m = Integer.parseInt(s.substring(3, 5));
return h * 60 + m;
}
}
class Solution {
public:
int numberOfRounds(string loginTime, string logoutTime) {
auto f = [](string& s) {
int h, m;
sscanf(s.c_str(), "%d:%d", &h, &m);
return h * 60 + m;
};
int a = f(loginTime), b = f(logoutTime);
if (a > b) {
b += 1440;
}
return max(0, b / 15 - (a + 14) / 15);
}
};
func numberOfRounds(loginTime string, logoutTime string) int {
f := func(s string) int {
var h, m int
fmt.Sscanf(s, "%d:%d", &h, &m)
return h*60 + m
}
a, b := f(loginTime), f(logoutTime)
if a > b {
b += 1440
}
return max(0, b/15-(a+14)/15)
}
function numberOfRounds(startTime: string, finishTime: string): number {
const f = (s: string): number => {
const [h, m] = s.split(':').map(Number);
return h * 60 + m;
};
let [a, b] = [f(startTime), f(finishTime)];
if (a > b) {
b += 1440;
}
return Math.max(0, Math.floor(b / 15) - Math.ceil(a / 15));
}