Fill in the method findKthLargest that does the following: 1) take one unsorted integer array and one
Question:
Fill in the method findKthLargest that does the following: 1) take one unsorted integer array and one
integer (k) as inputs, 2) return the k-th largest value in the integer array.
a. While there are other ways to solve this problem, you MUST use BinaryMinHeap to solve this
problem.
b. DO NOT MODIFY the methods and/or the lines that are commented with // DO NOT MODIFY
comment block.
public class BinaryMinHeap {
private int[] array ;
private int currentSize;
// DO NOT MODIFY
public BinaryMinHeap() {
array = new int[12];
currentSize = 0;
}
// DO NOT MODIFY
public BinaryMinHeap(int[] items) {
currentSize = items.length;
array = new int[(currentSize + 2)]; // just enough buffer
int i = 1;
for (int item: items) array[i++] = item;
buildHeap();
}
// DO NOT MODIFY
private void buildHeap() {
for (int i = currentSize/2; i > 0; i--) {
percolateDown(i);
}
}
// DO NOT MODIFY
private void enlargeArray(int newSize) {
int[] newArray = new int[newSize];
for (int i = 0; i < array.length; i++) {
newArray[i] = array[i];
}
array = newArray;
}
// DO NOT MODIFY
public void insert(int x) {
if (currentSize == array.length - 1) {
enlargeArray(array.length * 2 + 1);
}
// Percolate Up
int hole = ++currentSize;
for (array[0] = x; x < array[hole/2]; hole = hole/2) {
array[hole] = array[hole/2];
}
array[hole] = x;
}
// DO NOT MODIFY
public int deleteMin() {
int returnValue = array[1];
//moving the last one to the first; breaking the heap
array[1] = array[currentSize];
--currentSize;
percolateDown(1);
return returnValue;
}
// DO NOT MODIFY
private void percolateDown(int hole) {
int child;
int tmp = array[hole];
for(; hole * 2 <= currentSize; hole = child) {
child = hole * 2;
if (child != currentSize && array[child+1] < array[child]) {
child++;
}
if (array[child] < tmp) {
array[hole] = array[child];
} else {
break;
}
}
array[hole] = tmp;
}
// DO NOT MODIFY
public static int findKthSmallest(int[] array, int k) {
BinaryMinHeap myHeap = new BinaryMinHeap(array);
int returnValue = -1;
for (int i = 0; i < k; i++) {
returnValue = myHeap.deleteMin();
}
return returnValue;
}
public static int findKthLargest(int[] array, int k) {
BinaryMinHeap myHeap = new BinaryMinHeap(); // DO NOT MODIFY THIS LINE
// WRITE CODE HERE
return 0; // modify to the correct value
}
public static void main (String[] args) {
System.out.println("Find K-th Smallest: ");
int[] kthInput = {10, 50, 40, 75, 60, 65, 45};
System.out.println("2nd Smallest: " + findKthSmallest(kthInput, 2));
System.out.println("4th Smallest: " + findKthSmallest(kthInput, 4));
System.out.println("2nd Largest: " + findKthLargest(kthInput, 2)); // must print 65
System.out.println("4th Largest: " + findKthLargest(kthInput, 4)); // must print 50
}
}
Java How To Program Late Objects Version
ISBN: 9780136123712
8th Edition
Authors: Paul Deitel, Deitel & Associates