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| 1 | +import java.util.*; |
| 2 | +import java.io.*; |
| 3 | + |
| 4 | + |
| 5 | +abstract class Heap{ |
| 6 | + protected int capacity; |
| 7 | + protected int size; |
| 8 | + protected int []items; |
| 9 | + |
| 10 | + public Heap() |
| 11 | + { |
| 12 | + this.capacity = 10; |
| 13 | + this.size = 0; |
| 14 | + this.items = new int[capacity]; |
| 15 | + } |
| 16 | + |
| 17 | + public int getLeftChildIndex(int parentindex){ |
| 18 | + return 2*parentindex+1; |
| 19 | + } |
| 20 | + |
| 21 | + public int getRightChildIndex(int parentindex){ |
| 22 | + return 2*parentindex+2; |
| 23 | + } |
| 24 | + |
| 25 | + public int getParentIndex(int childIndex){ |
| 26 | + return (childIndex-1)/2; |
| 27 | + } |
| 28 | + |
| 29 | + public boolean hasLeftChild(int parentindex) |
| 30 | + { |
| 31 | + return getLeftChildIndex(parentindex) < size; |
| 32 | + } |
| 33 | + |
| 34 | + |
| 35 | + public boolean hasRightChild(int parentindex) |
| 36 | + { |
| 37 | + return getRightChildIndex(parentindex) < size; |
| 38 | + } |
| 39 | + |
| 40 | + public boolean hasParent(int index){ |
| 41 | + return getParentIndex(index) >= 0; |
| 42 | + } |
| 43 | + |
| 44 | + public int leftChild(int parentindex){ |
| 45 | + return items[getLeftChildIndex(parentindex)]; |
| 46 | + } |
| 47 | + |
| 48 | + public int rightChild(int parentindex){ |
| 49 | + return items[getRightChildIndex(parentindex)]; |
| 50 | + } |
| 51 | + |
| 52 | + public int parent(int index) |
| 53 | + { |
| 54 | + return items[getParentIndex(index)]; |
| 55 | + } |
| 56 | + |
| 57 | + public void swap(int indexone,int indextwo){ |
| 58 | + int temp = items[indexone]; |
| 59 | + items[indexone] = items[indextwo]; |
| 60 | + items[indextwo] = temp; |
| 61 | + } |
| 62 | + |
| 63 | + public void add(int item) |
| 64 | + { |
| 65 | + items[size] = item; |
| 66 | + size++; |
| 67 | + heapifyUp(); |
| 68 | + } |
| 69 | + public void isEmpty(String name) |
| 70 | + { |
| 71 | + if(size == 0) |
| 72 | + { |
| 73 | + System.out.println(name+"cant poll"); |
| 74 | + } |
| 75 | + } |
| 76 | + |
| 77 | + public int poll() |
| 78 | + { |
| 79 | + isEmpty("its empty"); |
| 80 | + |
| 81 | + int item = items[0]; |
| 82 | + items[0] = items[size-1]; |
| 83 | + size--; |
| 84 | + |
| 85 | + heapifyDown(); |
| 86 | + return item; |
| 87 | + } |
| 88 | + |
| 89 | + public void print() |
| 90 | + { |
| 91 | + for(int i=0;i<size;i++) |
| 92 | + { |
| 93 | + System.out.print(items[i]); |
| 94 | + } |
| 95 | + } |
| 96 | + |
| 97 | + public abstract void heapifyDown(); |
| 98 | + |
| 99 | + public abstract void heapifyUp(); |
| 100 | + |
| 101 | +} |
| 102 | +class MaxHeap extends Heap |
| 103 | +{ |
| 104 | + public void heapifyDown() |
| 105 | + { |
| 106 | + int index = 0; |
| 107 | + |
| 108 | + while(hasLeftChild(index)){ |
| 109 | + int smallerChildIndex = getLeftChildIndex(index); |
| 110 | + |
| 111 | + if(hasRightChild(index) && rightChild(index) > leftChild(index)) |
| 112 | + { |
| 113 | + smallerChildIndex = getRightChildIndex(index); |
| 114 | + } |
| 115 | + |
| 116 | + if(items[index] > items[smallerChildIndex]) |
| 117 | + { |
| 118 | + break; |
| 119 | + } |
| 120 | + else{ |
| 121 | + swap(index,smallerChildIndex); |
| 122 | + } |
| 123 | + index = smallerChildIndex; |
| 124 | + } |
| 125 | + } |
| 126 | + |
| 127 | + |
| 128 | + public void heapifyUp() |
| 129 | + { |
| 130 | + int index = size - 1; |
| 131 | + while(hasParent(index) && parent(index) < items[index]){ |
| 132 | + swap(getParentIndex(index),index); |
| 133 | + index = getParentIndex(index); |
| 134 | + } |
| 135 | + } |
| 136 | + |
| 137 | + public static void main(String []args) |
| 138 | + { |
| 139 | + Scanner ob = new Scanner(System.in); |
| 140 | + int n = ob.nextInt(); |
| 141 | + Heap myHeap = new MaxHeap(); |
| 142 | + for(int i=0;i<n;i++) |
| 143 | + { |
| 144 | + myHeap.add(ob.nextInt()); |
| 145 | + } |
| 146 | + |
| 147 | + myHeap.print(); |
| 148 | + System.out.println("Element removed:"+myHeap.poll()); |
| 149 | + myHeap.print(); |
| 150 | + } |
| 151 | +} |
| 152 | + |
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