text: Frequency Measuring Techniques for Competitive Programming | Javascript program to count frequencies of array items ; Mark all array elements as not visited ; Traverse through array elements and count frequencies ; Skip this element if already processed ; Count frequency ; Driver Code
code: function countFreq ( arr , n ) { let visited = new Array ( n ) ; visited . fill ( false ) ; for ( let i = 0 ; i < n ; i ++ ) { if ( visited [ i ] == true ) continue ; let count = 1 ; for ( let j = i + 1 ; j < n ; j ++ ) { if ( arr [ i ] == arr [ j ] ) { visited [ j ] = true ; count ++ ; } } document . write ( arr [ i ] + " " + count + " " ) ; } } let arr = [ 10 , 20 , 20 , 10 , 10 , 20 , 5 , 20 ] ; let n = arr . length ; countFreq ( arr , n ) ;