Given a positive integer N, check if it is Pythagorean prime or not. If it is a Pythagorean prime, print ‘Yes’ otherwise print ‘No’.
Pythagorean primes : A prime number of the form 4*n + 1 is a Pythagorean prime. It can also be expressed as sum of two squares.
Pythagorean primes in the range 1 – 100 are:
5, 13, 17, 29, 37, 41, 53, 61, 73, 89, 97
Examples:
Input : N = 5 Output : Yes Explanation : 5 is a prime number and can be expressed in the form ( 4*n + 1 ) as ( 4*1 + 1 ). Input : N = 13 Output : Yes Explanation: 13 is a prime number and can be expressed in the form ( 4*n + 1 ) as ( 4*3 + 1 ).
A Simple Solution is to check first if the given number is prime or not and can be written in the form of 4*n + 1 or not. If yes, Then the number is Pythagorean prime, otherwise not.
Below is the implementation of the above approach
C++
// CPP program to check if a number is // Pythagorean prime or not #include <bits/stdc++.h> using namespace std; // Function to check if a number is // prime or not bool isPrime( int n) { // Corner cases if (n <= 1) return false ; if (n <= 3) return true ; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) return false ; for ( int i = 5; i * i <= n; i = i + 6) { if (n % i == 0 || n % (i + 2) == 0) { return false ; } } return true ; } // Driver Program int main() { int n = 13; // Check if number is prime // and of the form 4*n+1 if (isPrime(n) && (n % 4 == 1)) { cout << "YES" ; } else { cout << "NO" ; } return 0; } |
Java
// JAVA program to check if a number is // Pythagorean prime or not class GFG { // Function to check if a number // is prime or not static boolean isPrime( int n) { // Corner cases if (n <= 1 ) return false ; if (n <= 3 ) return true ; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0 ) return false ; for ( int i = 5 ; i * i <= n; i = i + 6 ) { if (n % i == 0 || n % (i + 2 ) == 0 ) { return false ; } } return true ; } // Driver Program public static void main(String[] args) { int n = 13 ; // Check if number is prime // and of the form 4n+1 if (isPrime(n) && (n % 4 == 1 )) { System.out.println( "YES" ); } else { System.out.println( "NO" ); } } } |
Python3
# Python 3 program to check if a number is # Pythagorean prime or not # Utility function to check # if a number is prime or not def isPrime(n) : # Corner cases if (n < = 1 ) : return False if (n < = 3 ) : return True # This is checked so that we can skip # middle five numbers in below loop if (n % 2 = = 0 or n % 3 = = 0 ) : return False i = 5 while (i * i < = n) : if (n % i = = 0 or n % (i + 2 ) = = 0 ) : return False i = i + 6 return True # Driver Code n = 13 # Check if number is prime # and of the form 4n + 1 if (isPrime(n) and (n % 4 = = 1 )): print ( "YES" ) else : print ( "NO" ) |
C#
// C# program to check if a number // is Pythagorean prime or not using System; class GFG { // Function to check if a number // is prime or not static bool isPrime( int n) { // Corner cases if (n <= 1) { return false ; } if (n <= 3) { return true ; } // This is checked so that we // can skip middle five numbers // in below loop if (n % 2 == 0 || n % 3 == 0) { return false ; } for ( int i = 5; i * i <= n; i = i + 6) { if (n % i == 0 || n % (i + 2) == 0) { return false ; } } return true ; } // Driver Code public static void Main( string [] args) { int n = 13; // Check if number is prime // and of the form 4n+1 if (isPrime(n) && (n % 4 == 1)) { Console.WriteLine( "YES" ); } else { Console.WriteLine( "NO" ); } } } // This code is contributed by Shrikant13 |
PHP
<?php // PHP program to check if // a number is Pythagorean // prime or not // Function to check if a // number is prime or not function isPrime( $n ) { // Corner cases if ( $n <= 1) return false; if ( $n <= 3) return true; // This is checked so that // we can skip middle five // numbers in below loop if ( $n % 2 == 0 or $n % 3 == 0) return false; for ( $i = 5; $i * $i <= $n ; $i = $i + 6) { if ( $n % $i == 0 or $n % ( $i + 2) == 0) { return false; } } return true; } // Driver Code $n = 13; // Check if number is prime // and of the form 4*n+1 if (isPrime( $n ) && ( $n % 4 == 1)) { echo "YES" ; } else { echo "NO" ; } // This code is contributed // by inder_verma ?> |
Javascript
<script> // Javascript program to check if a number is // Pythagorean prime or not // Function to check if a number is // prime or not function isPrime(n) { // Corner cases if (n <= 1) return false ; if (n <= 3) return true ; // This is checked so that we can skip // middle five numbers in below loop if (n % 2 == 0 || n % 3 == 0) return false ; for ( var i = 5; i * i <= n; i = i + 6) { if (n % i == 0 || n % (i + 2) == 0) { return false ; } } return true ; } // Driver Program var n = 13; // Check if number is prime // and of the form 4*n+1 if (isPrime(n) && (n % 4 == 1)) { document.write( "YES" ); } else { document.write( "NO" ); } // This code is contributed by itsok. </script> |
YES
Time Complexity: O(sqrt(n))
Auxiliary Space: O(1)
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