Only the sort of the int type is considered, and the generic implementation is considered later.

1 Public classHeap {2 3 Public intHeap_size;//initialized in Build_max_heap, automatically called by Heap_sort4 5 Public intParentinti) {6 return(i-1)/2;7 }8 Public intLeftinti) {9 return2 * i + 1;Ten } One Public intRightinti) { A return2 * i + 2; - } - the /**keep the nature of the heap, - * Assuming left (i), right (i) is the root of the two binary tree is the largest heap, - * A[i] may be smaller than its children, thus violating the maximum heap properties - * This function allows a[i] to "descend" in the maximum heap, making the subtree with the root of I as the largest heap + * */ - Public voidMax_heapify (int[] A,inti) { + intL =Left (i); A intR =Right (i); at intlargest; - //from A[i] A[left (i)] a[right (i)] to find the largest, subscript exists in largest - //if A[i] is the largest, then it is assumed that I is the root of the subtree is already the largest heap, function end - //otherwise interchange a[i] and A[largest], the value of the node labeled largest after the interchange is A[i] - //The subtree of the node may violate the maximum heap, so recursive invocation of largest subscript - if(L < heap_size && A[l] >A[i]) { inlargest =l; - } to Else{ +largest =i; - } the if(R < heap_size && A[r] >A[largest]) { *largest =R; $ }Panax Notoginseng if(Largest! =i) { - intTMP =A[i]; theA[i] =A[largest]; +A[largest] =tmp; A the max_heapify (A, largest); + } - } $ $ /** - * Build a heap - * Bottom-up array A[1..N] (here N=length[a]) becomes the maximum heap the * Sub-array a[(Floor (N/2) + 1): Elements in the tree are all leaves - * So the process is called once for each non-leaf nodeWuyi * */ the Public voidBuild_max_heap (int[] A) { -Heap_size = A.length;//Initialize Heap_size Wu for(inti = (HEAP_SIZE/2-1); i >-1; --i) { - max_heapify (A, i); About } $ } - - /** - * Heap Sorting algorithm A * First build the largest heap, root a[1] is the largest, then displace to the correct position of the array a[n] + * Remove nodes from the heap n,a[1..n-1] built the largest heap, but the new root may violate the maximum heap properties, the * The call max_heapify (a,1) can maintain the property at this time, constructing the maximum heap in a[1..n-1]. - * Repeat, heap size reduced from n-1 to 2 $ * */ the Public voidHeapsort (int[] A) { the build_max_heap (A); the for(inti = a.length-1; i > 0; --i) { the intTMP = A[0]; -A[0] =A[i]; inA[i] =tmp; the--heap_size; theMax_heapify (A, 0); About } the } the the Public Static voidShow_array (int[] A) { + for(inti = 0; i < a.length; ++i) { -System.out.print (A[i] + "."); the }Bayi System.out.println (); the } the - Public Static voidMain (string[] args) { - int[] A = {4, 1, 3, 2, 16, 9, 10, 14, 8, 7}; the

the theSystem.out.println ("Before Heapsort:"); the Show_array (A); - theHeap h =NewHeap (); the H.heapsort (A); the 94System.out.println ("After Heapsort:"); the Show_array (A); the the }98 About}

Operation Result:

6th Heap Sorting Java implementation of the simplest version