Find prime number K in an array such that ( A [ i ] % K ) is maximum | Function to return the required prime number from the array ; Find maximum value in the array ; USE SIEVE TO FIND ALL PRIME NUMBERS LESS THAN OR EQUAL TO max_val Create a boolean array " prime [ 0 . . n ] " . A value in prime [ i ] will finally be false if i is Not a prime , else true . ; Remaining part of SIEVE ; If prime [ p ] is not changed , then it is a prime ; Update all multiples of p ; To store the maximum prime number ; If current element is prime then update the maximum prime ; Return the maximum prime number from the array ; Driver code
function getPrime ( arr , n ) { let max_val = Math . max ( ... arr ) ; let prime = new Array ( max_val + 1 ) . fill ( true ) ; prime [ 0 ] = false ; prime [ 1 ] = false ; for ( let p = 2 ; p * p <= max_val ; p ++ ) { if ( prime [ p ] == true ) { for ( let i = p * 2 ; i <= max_val ; i += p ) prime [ i ] = false ; } } let maximum = - 1 ; for ( let i = 0 ; i < n ; i ++ ) { if ( prime [ arr [ i ] ] ) maximum = Math . max ( maximum , arr [ i ] ) ; } return maximum ; } let arr = [ 2 , 10 , 15 , 7 , 6 , 8 , 13 ] ; let n = arr . length ; document . write ( getPrime ( arr , n ) ) ;