Length of the smallest number which is divisible by K and formed by using 1 's only | Function to return length of the resultant number ; If K is a multiple of 2 or 5 ; Generate all possible numbers 1 , 11 , 111 , 111 , ... , K 1 's ; If number is divisible by k then return the length ; Driver code
< ? php function numLen ( $ K ) { if ( $ K % 2 == 0 $ K % 5 == 0 ) return -1 ; $ number = 0 ; $ len = 1 ; for ( $ len = 1 ; $ len <= $ K ; $ len ++ ) { $ number = $ number * 10 + 1 ; if ( ( $ number % $ K == 0 ) ) return $ len ; } return -1 ; } $ K = 7 ; echo numLen ( $ K ) ; ? >