Legendre’s Formula in java

You can calculate the exponent of the largest power of a PrimeNumber that divides the factorial n! using Legendre's formula.

Program

import java.util.Scanner;

public class LegendresFormula {
   static int Largestpower(int n, int p) {
      int ans = 0;
      while (n > 0) {
         n /= p;
         ans += n;
      }
      return ans;
   }
   public static void main (String[] args) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter the n value :");
      int n = sc.nextInt();
      System.out.println("Enter the p value :");
     
      int p = sc.nextInt();
      int temp = n;
      int result = 0;
     
      while (temp > 0) {
         temp = temp / p;
         result = result + temp;
      }
      System.out.println("Largest power of "+p +" that divides "+ n+"! is :"+result);
   }
}

Output

Enter the n value :
20
Enter the p value :
6
Largest power of 6 that divides 20! is :3

George John

Updated on: 25-Jun-2020

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