[LeetCode] 1344. Angle Between Hands of a Clock

Given two numbers, hour and minutes. Return the smaller angle (in degrees) 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.

时钟指针的夹角。题意很直观。

思路也很直观，首先定义好一分钟的夹角是6度，一小时的夹角是30度。接着根据这个定义分别算出时针和分针与0：00这个位置的夹角。注意最后两者的夹角一定不会大于360度。

时间O(1)

空间O(1)

Java实现

class Solution {
    public double angleClock(int hour, int minutes) {
        int oneMinAngle = 6;
        int oneHourAngle = 30;
        double minutesAngle = oneMinAngle * minutes;
        double hoursAngle = (hour % 12 + minutes / 60.0) * oneHourAngle;
        double diff = Math.abs(hoursAngle - minutesAngle);
        return Math.min(diff, 360 - diff);
    }
}

JavaScript实现

/**
 * @param {number} hour
 * @param {number} minutes
 * @return {number}
 */
var angleClock = function(hour, minutes) {
    let oneMinuteAngle = 6;
    let oneHourAngle = 30;
    let minutesAngle = oneMinuteAngle * minutes;
    let hoursAngle = ((hour % 12) + minutes / 60.0) * oneHourAngle;
    let diff = Math.abs(hoursAngle - minutesAngle);
    return Math.min(diff, 360 - diff);
};

LeetCode 题目总结