Print all possible combinations of r elements in a given array of size n | The main function that prints all combinations of size r in arr [ ] of size n . This function mainly uses combinationUtil ( ) ; A temporary array to store all combination one by one ; Print all combination using temprary array ' data [ ] ' ; arr [ ] -- -> Input Array data [ ] -- -> Temporary array to store current combination start & end -- -> Staring and Ending indexes in arr [ ] index -- -> Current index in data [ ] r -- -> Size of a combination to be printed ; Current combination is ready to be printed , print it ; When no more elements are there to put in data [ ] ; current is included , put next at next location ; current is excluded , replace it with next ( Note that i + 1 is passed , but index is not changed ) ; Driver function to check for above function
function printCombination ( arr , n , r ) { let data = new Array ( r ) ; combinationUtil ( arr , n , r , 0 , data , 0 ) ; } function combinationUtil ( arr , n , r , index , data , i ) { if ( index == r ) { for ( let j = 0 ; j < r ; j ++ ) { document . write ( data [ j ] + " " ) ; } document . write ( " " ) ; return ; } if ( i >= n ) { return ; } data [ index ] = arr [ i ] ; combinationUtil ( arr , n , r , index + 1 , data , i + 1 ) ; combinationUtil ( arr , n , r , index , data , i + 1 ) ; } let arr = [ 1 , 2 , 3 , 4 , 5 ] ; let r = 3 ; let n = arr . length ; printCombination ( arr , n , r ) ;