Angle between Hour and Minute Hand

Problem

Calculate the angle between the hour hand and minute hand.

Note: There can be two angles between hands; we need to print a minimum of two. Also, we need to print the floor of the final result angle. For example, if the final angle is 10.61, we need to print 10.

Examples:

Example 1:

Input:
H = 9 , M = 0
Output:
90
Explanation:
The minimum angle between hour and minute hand when the time is 9 is 90 degress.

Example 2:

Input:
H = 3 , M = 30
Output:
75
Explanation:
The minimum angle between hour and minute hand when the time is 3:30 is 75 degress.

Your task:

You don't need to read, input, or print anything. Your task is to complete the function getAngle(), which takes 2 Integers H and M as input and returns the answer.

• Expected Time Complexity: $O(1)$
• Expected Auxiliary Space: $O(1)$

Constraints:

• $1 ≤ H ≤ 12$
• $0 ≤ M < 60$

H and M are Integers

Solution

Python

def getAngle(self, H , M):
    if H < 0 or M < 0 or H > 12 or M > 60:
        print('Wrong input')
        return None
    if H == 12:
        H = 0
    if M == 60:
        M = 0
        H += 1
        if H > 12:
            H -= 12
    hour_angle = 0.5 * (H * 60 + M)
    minute_angle = 6 * M
    angle = abs(hour_angle - minute_angle)
    angle = min(360 - angle, angle)
    return int(angle)

Java

static int getAngle(int H , int M) {
    if (H < 0 || M < 0 || H > 12 || M > 60) {
        System.out.println("Wrong input");
        return -1; 
    }
    if (H == 12) {
        H = 0;
    }
    if (M == 60) {
        M = 0;
        H += 1;
        if (H > 12) {
            H -= 12;
        }
    }
    double hourAngle = 0.5 * (H * 60 + M);
    double minuteAngle = 6 * M;
    double angle = Math.abs(hourAngle - minuteAngle);
    angle = Math.min(360 - angle, angle);
    return (int) angle;
}

C++

int getAngle(int H , int M) {
    if (H < 0 || M < 0 || H > 12 || M > 60) {
        cout << "Wrong input" << endl;
        return -1; 
    }
    if (H == 12) {
        H = 0;
    }
    if (M == 60) {
        M = 0;
        H += 1;
        if (H > 12) {
            H -= 12;
        }
    }
    double hourAngle = 0.5 * (H * 60 + M);
    double minuteAngle = 6 * M;
    double angle = abs(hourAngle - minuteAngle);
    angle = min(360 - angle, angle);
    return static_cast<int>(angle);
}

C

int getAngle(int H, int M) {
    if (H < 0 || M < 0 || H > 12 || M > 60) {
        printf("Wrong input\n");
        return -1; 
    }
    if (H == 12) {
        H = 0;
    }
    if (M == 60) {
        M = 0;
        H += 1;
        if (H > 12) {
            H -= 12;
        }
    }
    double hourAngle = 0.5 * (H * 60 + M);
    double minuteAngle = 6 * M;
    double angle = fabs(hourAngle - minuteAngle);
    angle = fmin(360 - angle, angle);
    return (int)angle;
}

• Time Complexity: $O(1)$
• Auxiliary Space: $O(1)$