花花酱 LeetCode 1344. Angle Between Hands of a Clock

Given two numbers, hour and minutes. Return the smaller angle (in sexagesimal units) formed between the hour and the minute hand.

Example 1:

Input: hour = 12, minutes = 30
Output: 165

Example 2:

Input: hour = 3, minutes = 30
Output: 75

Example 3:

Input: hour = 3, minutes = 15
Output: 7.5

Example 4:

Input: hour = 4, minutes = 50
Output: 155

Example 5:

Input: hour = 12, minutes = 0
Output: 0

Constraints:

• 1 <= hour <= 12
• 0 <= minutes <= 59
• Answers within 10^-5 of the actual value will be accepted as correct.

Solution: Math

1. Compute the angle of the hour hand (h + m / 60.0) * 360 / 12 as a_h
2. Compute the angle of the minute hand m / 60.0 * 360 as a_m
3. ans = min(abs(a_h – a_m), 360 – abs(a_h – a_m))

Time complexity: O(1)
Space complexity: O(1)