Largest number less than or equal to N / 2 which is coprime to N | Function to calculate gcd of two number ; Function to check if two numbers are coprime or not ; two numbers are coprime if their gcd is 1 ; Function to find largest integer less than or equal to N / 2 and coprime with N ; Check one by one all numbers less than or equal to N / 2 ; Driver code
function gcd ( a , b ) { if ( b == 0 ) return a ; else return gcd ( b , a % b ) ; } function coPrime ( n1 , n2 ) { if ( gcd ( n1 , n2 ) == 1 ) return true ; else return false ; } function largestCoprime ( N ) { let half = Math . floor ( N / 2 ) ; while ( coPrime ( N , half ) == false ) half -- ; return half ; } let n = 50 ; document . write ( largestCoprime ( n ) ) ;