Calculate the IST : Indian Standard Time - GeeksforGeeks

28 Mar, 2022
Given two integer H and R where H is the time in hours at a place X and R is the distance in degrees from place X to India, the task is to find the current time in IST.UTC (Coordinated Universal Time) is a 24-hour time standard that is used to synchronize world clocks.Examples:  
Input: H = 24, R = 82.50 Output: IST = 5:30 IST = (24/360)* 82.50 = 5.5 = 0.5*60 (i.e 60 minute = 360 degree rotation and 1 minute = 6 degree so, 0.5 hour * 60 = 30) IST = 5:30Input: H = 20, R = 150 Output: IST = 8:20  
 
Approach:  
It is known that 1 hour = 60 minute = 360 degree rotation.
1 degree rotation = (1 / 360) hour.
2 degree rotation = (1 / 360) * 2 hour.
So, Generalised formula will be:
 
IST = UTC + (H / 360) * R (UTC = 0 for IST)
IST = ( H / 360 ) * R
The answer will be converted in 0:00 form so int part (hour) and float part in IST are separated and the float part is multiplied by 60 to convert it into minutes.Below is the implementation of the above approach:  
C++
Java
Python3
C#
Javascript
// C++ implementation of the approach#include <cmath>#include <iostream>using namespace std; // Function to calculate Indian Standard Timevoid cal_IST(int h, float r){    float IST = (h * r * 1.0) / 360;     // Separate integer part    int int_IST = (int)IST;     // Separate float part and return ceil value    int float_IST = ceil((IST - int_IST) * 60);     cout << int_IST << ":" << float_IST;} // Driver codeint main(){     // Number of hours (1 - 24)    int h = 20;     // Rotations in degrees    float r = 150;     cal_IST(h, r);     return 0;}
// Java implementation of the approachimport java.math.*; class GFG{    // Function to calculate Indian Standard Time    public static void cal_IST(int h, double r)    {        double IST = (h * r * 1.0) / 360;         // Separate integer part        int int_IST = (int)IST;         // Separate float part and return ceil value        int float_IST = (int)Math.ceil((int)((IST - int_IST) * 60));         System.out.println(int_IST + ":" + float_IST);    }     // Driver code    public static void main(String[] args)    {             // Number of hours (1 - 24)        int h = 20;             // Rotations in degrees        double r = 150;             cal_IST(h, r);    }} // This code is contributed by Naman_Garg
# Python3 implementation of the approachfrom math import ceil # Function to calculate Indian Standard Timedef cal_IST(h, r) :     IST = round((h * r * 1.0) / 360, 3);     # Separate integer part    int_IST = int(IST);     # Separate float part and return ceil value    float_IST = ceil((IST - int_IST) * 60);     print(int_IST, ":", float_IST); # Driver codeif __name__ == "__main__" :     # Number of hours (1 - 24)    h = 20;     # Rotations in degrees    r = 150;     cal_IST(h, r); # This code is contributed by AnkitRai01
// C# implementation of the approachusing System; class GFG{    // Function to calculate Indian Standard Time    public static void cal_IST(int h, double r)    {        double IST = (h * r * 1.0) / 360;         // Separate integer part        int int_IST = (int)IST;         // Separate float part and return ceil value        int float_IST = (int)Math.Floor((                         double)(IST - int_IST) * 60);         Console.WriteLine(int_IST + ":" + float_IST);    }     // Driver code    public static void Main(String[] args)    {             // Number of hours (1 - 24)        int h = 20;             // Rotations in degrees        double r = 150;             cal_IST(h, r);    }} // This code is contributed by PrinciRaj1992
<script>// Javascript implementation of the approach // Function to calculate Indian Standard Timefunction cal_IST(h, r){    let IST = (h * r * 1.0) / 360;     // Separate integer part    let int_IST = parseInt(IST);     // Separate float part and return ceil value    let float_IST = Math.ceil(parseInt((IST - int_IST) * 60));     document.write(int_IST + ":" + float_IST);} // Driver code     // Number of hours (1 - 24)    let h = 20;     // Rotations in degrees    let r = 150;     cal_IST(h, r); // This code is contributed by subhammahato348.</script>
8:20
 
Time Complexity: O(1)
Auxiliary Space: O(1)
ankthon
Naman_Garg
princiraj1992
subhammahato348
Mathematical
Mathematical
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