HeapSort | To heapify a subtree rooted with node i which is an index in arr [ ] . n is size of heap ; Initialize largest as root ; left = 2 * i + 1 ; right = 2 * i + 2 ; If left child is larger than root ; If right child is larger than largest so far ; If largest is not root ; Recursively heapify the affected sub - tree ; The main function to sort an array of given size ; Build heap ( rearrange array ) ; One by one extract an element from heap ; Move current root to end ; call max heapify on the reduced heap ; A utility function to print array of size n ; Driver code
function heapify ( arr , n , i ) { var largest = i ; var l = 2 * i + 1 ; var r = 2 * i + 2 ; if ( l < n && arr [ l ] > arr [ largest ] ) largest = l ; if ( r < n && arr [ r ] > arr [ largest ] ) largest = r ; if ( largest != i ) { var swap = arr [ i ] ; arr [ i ] = arr [ largest ] ; arr [ largest ] = swap ; heapify ( arr , n , largest ) ; } } function sort ( arr ) { var n = arr . length ; for ( var i = n / 2 - 1 ; i >= 0 ; i -- ) heapify ( arr , n , i ) ; for ( var i = n - 1 ; i > 0 ; i -- ) { var temp = arr [ 0 ] ; arr [ 0 ] = arr [ i ] ; arr [ i ] = temp ; heapify ( arr , i , 0 ) ; } } function printArray ( arr ) { var n = arr . length ; for ( var i = 0 ; i < n ; ++ i ) document . write ( arr [ i ] + " " ) ; } var arr = [ 12 , 11 , 13 , 5 , 6 , 7 ] ; var n = arr . length ; sort ( arr ) ; document . write ( " " ) ; printArray ( arr , n ) ;