Inserts the prime factor in the Hash Map if not present If present updates it 's frequency
public static Dictionary < int , int > insertPF ( Dictionary < int , int > primeFact , int fact ) { if ( primeFact . ContainsKey ( fact ) ) { int freq ; freq = primeFact [ fact ] ; primeFact [ fact ] = ++ freq ; } else { primeFact . Add ( fact , 1 ) ; } return primeFact ; }