Add files via upload

Author: skjha1

Heap/06 HeapifyFunctionFasterMethodtoCreateHeap.cpp

@@ -0,0 +1,88 @@
+#include <iostream>
+
+using namespace std;
+ 
+void swap(int A[], int i, int j){
+    int temp = A[i];
+    A[i] = A[j];
+    A[j] = temp;
+}
+ 
+int Delete(int A[], int n){
+    int x = A[0];  // Max element
+    A[0] = A[n-1];
+ 
+    int i = 0;
+    int j = 2 * i + 1;
+ 
+    while (j < n-1){
+        // Compare left and right children
+        if (A[j] < A[j+1]){
+            j = j+1;
+        }
+ 
+        // Compare parent and largest child
+        if (A[i] < A[j]){
+            swap(A, i, j);
+            i = j;
+            j = 2 * i + 1;
+        } else {
+            break;
+        }
+    }
+    return x;
+}
+ 
+void Heapify(int A[], int n){
+    // # of leaf elements: (n+1)/2, index of last leaf element's parent = (n/2)-1
+    for (int i=(n/2)-1; i>=0; i--){
+ 
+        int j = 2 * i + 1;  // Left child for current i
+ 
+        while(j < n-1){
+            // Compare left and right children of current i
+            if (A[j] < A[j+1]){
+                j = j+1;
+            }
+ 
+            // Compare parent and largest child
+            if (A[i] < A[j]){
+                swap(A, i, j);
+                i = j;
+                j = 2 * i + 1;
+            } else {
+                break;
+            }
+        }
+    }
+}
+ 
+template <class T>
+void Print(T& vec, int n, string s){
+    cout << s << ": [" << flush;
+    for (int i=0; i<n; i++){
+        cout << vec[i] << flush;
+        if (i < n-1){
+            cout << ", " << flush;
+        }
+    }
+    cout << "]" << endl;
+}
+ 
+int main() {
+ 
+    int A[] = {5, 10, 30, 20, 35, 40, 15};
+    Print(A, sizeof(A)/sizeof(A[0]), "A");
+ 
+    Heapify(A, sizeof(A)/sizeof(A[0]));
+    Print(A, sizeof(A)/sizeof(A[0]), "Heapified A");
+    cout << endl;
+ 
+    int B[] = {5, 10, 30, 20};
+    Print(B, sizeof(B)/sizeof(B[0]), "B");
+ 
+    Heapify(B, sizeof(B)/sizeof(B[0]));
+    Print(B, sizeof(B)/sizeof(B[0]), "Heapified B");
+ 
+    return 0;
+}