93 lines
2.6 KiB
Java
93 lines
2.6 KiB
Java
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/** Author : Suraj Kumar Modi
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* https://github.com/skmodi649
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*/
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/** You are given a number n. You need to find the digital root of n.
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* DigitalRoot of a number is the recursive sum of its digits until we get a single digit number.
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*
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* Test Case 1:
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* Input:
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* n = 1
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* Output: 1
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* Explanation: Digital root of 1 is 1
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*
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* Test Case 2:
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* Input:
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* n = 99999
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* Output: 9
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* Explanation: Sum of digits of 99999 is 45
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* which is not a single digit number, hence
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* sum of digit of 45 is 9 which is a single
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* digit number.
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*/
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/** Algorithm :
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* Step 1 : Define a method digitalRoot(int n)
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* Step 2 : Define another method single(int n)
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* Step 3 : digitalRoot(int n) method takes output of single(int n) as input
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if(single(int n) <= 9)
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return single(n)
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else
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return digitalRoot(single(n))
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* Step 4 : single(int n) calculates the sum of digits of number n recursively
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if(n<=9)
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return n;
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else
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return (n%10) + (n/10)
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* Step 5 : In main method simply take n as input and then call digitalRoot(int n) function and print the result
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*/
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package Maths;
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import java.util.*;
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import java.io.*;
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import java.lang.*;
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class DigitalRoot
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{
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public static int digitalRoot(int n)
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{
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if(single(n) <= 9) // If n is already single digit than simply call single method and return the value
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return single(n);
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else
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return digitalRoot(single(n));
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}
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// This function is used for finding the sum of digits of number
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public static int single(int n)
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{
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if(n<=9) // if n becomes less than 10 than return n
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return n;
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else
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return (n % 10) + single(n / 10); // n % 10 for extracting digits one by one
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} // n / 10 is the number obtainded after removing the digit one by one
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// Sum of digits is stored in the Stack memory and then finally returned
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public static void main(String[] args)
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{
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Scanner sc = new Scanner(System.in);
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System.out.println("Enter the number : ");
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int n = sc.nextInt(); // Taking a number as input from the user
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System.out.println("Digital Root : "+digitalRoot(n)); // Printing the value returned by digitalRoot() method
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}
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}
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/**
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* Time Complexity : O((Number of Digits)^2)
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* Auxiliary Space Complexity : O(Number of Digits)
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* Constraints : 1 <= n <= 10^7
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*/
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