Check if the first and last digit of the smallest number forms a prime | Python3 implementation of above approach ; function to check prime ; Function to generate smallest possible number with given digits ; Declare a Hash array of size 10 and initialize all the elements to zero ; store the number of occurrences of the digits in the given array into the Hash table ; Traverse the Hash in ascending order to print the required number ; Print the number of times a digits occurs ; extracting the first digit ; extracting the last digit ; printing the prime combinations ; Driver code
import math as mt NEW_LINE def isPrime ( n ) : NEW_LINE INDENT i , c = 0 , 0 NEW_LINE for i in range ( 1 , n // 2 ) : NEW_LINE INDENT if ( n % i == 0 ) : NEW_LINE INDENT c += 1 NEW_LINE DEDENT DEDENT if ( c == 1 ) : NEW_LINE INDENT return 1 NEW_LINE DEDENT else : NEW_LINE INDENT return 0 NEW_LINE DEDENT DEDENT def findMinNum ( arr , n ) : NEW_LINE INDENT first , last = 0 , 0 NEW_LINE Hash = [ 0 for i in range ( 10 ) ] NEW_LINE for i in range ( n ) : NEW_LINE INDENT Hash [ arr [ i ] ] += 1 NEW_LINE DEDENT print ( " Minimum ▁ number : ▁ " , end = " " ) NEW_LINE for i in range ( 0 , 10 ) : NEW_LINE INDENT for j in range ( Hash [ i ] ) : NEW_LINE INDENT print ( i , end = " " ) NEW_LINE DEDENT DEDENT print ( ) NEW_LINE for i in range ( 10 ) : NEW_LINE INDENT if ( Hash [ i ] != 0 ) : NEW_LINE INDENT first = i NEW_LINE break NEW_LINE DEDENT DEDENT for i in range ( 9 , - 1 , - 1 ) : NEW_LINE INDENT if ( Hash [ i ] != 0 ) : NEW_LINE INDENT last = i NEW_LINE break NEW_LINE DEDENT DEDENT num = first * 10 + last NEW_LINE rev = last * 10 + first NEW_LINE print ( " Prime ▁ combinations : ▁ " , end = " " ) NEW_LINE if ( isPrime ( num ) and isPrime ( rev ) ) : NEW_LINE INDENT print ( num , " ▁ " , rev ) NEW_LINE DEDENT elif ( isPrime ( num ) ) : NEW_LINE INDENT print ( num ) NEW_LINE DEDENT elif ( isPrime ( rev ) ) : NEW_LINE INDENT print ( rev ) NEW_LINE DEDENT else : NEW_LINE INDENT print ( " No ▁ combinations ▁ exist " ) NEW_LINE DEDENT DEDENT arr = [ 1 , 2 , 4 , 7 , 8 ] NEW_LINE findMinNum ( arr , 5 ) NEW_LINE