Number which has the maximum number of distinct prime factors in the range M to N | Function to return the maximum number ; array to store the number of distinct primes ; true if index ' i ' is a prime ; initializing the number of factors to 0 and ; Used in Sieve ; condition works only when ' i ' is prime , hence for factors of all prime number , the prime status is changed to false ; Number is prime ; number of factor of a prime number is 1 ; incrementing factorCount all the factors of i ; and changing prime status to false ; Initialize the max and num ; Gets the maximum number ; Gets the maximum number ; Driver code ; Calling function
< ? php function maximumNumberDistinctPrimeRange ( $ m , $ n ) { $ factorCount = array ( ) ; $ prime = array ( ) ; for ( $ i = 0 ; $ i <= $ n ; $ i ++ ) { $ factorCount [ $ i ] = 0 ; $ prime [ $ i ] = true ; } for ( $ i = 2 ; $ i <= $ n ; $ i ++ ) { if ( $ prime [ $ i ] == true ) { $ factorCount [ $ i ] = 1 ; for ( $ j = $ i * 2 ; $ j <= $ n ; $ j += $ i ) { $ factorCount [ $ j ] ++ ; $ prime [ $ j ] = false ; } } } $ max = $ factorCount [ $ m ] ; $ num = $ m ; for ( $ i = $ m ; $ i <= $ n ; $ i ++ ) { if ( $ factorCount [ $ i ] > $ max ) { $ max = $ factorCount [ $ i ] ; $ num = $ i ; } } return $ num ; } $ m = 4 ; $ n = 6 ; echo maximumNumberDistinctPrimeRange ( $ m , $ n ) ; ? >