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fix documentations and cpplint

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This commit is contained in:
Krishna Vedala
2020-06-04 23:15:43 -04:00
parent 6635c0a1af
commit aacaf9828c
6 changed files with 174 additions and 159 deletions
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78
data_structures/binaryheap.cpp
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@@ -1,48 +1,52 @@
// A C++ program to demonstrate common Binary Heap Operations
/**
* \file
* \brief A C++ program to demonstrate common Binary Heap Operations
*/
#include <climits>
#include <iostream>
using namespace std;
#include <utility>
// Prototype of a utility function to swap two integers
void swap(int *x, int *y);
// A class for Min Heap
/** A class for Min Heap */
class MinHeap {
int *harr; // pointer to array of elements in heap
int capacity; // maximum possible size of min heap
int heap_size; // Current number of elements in min heap
int *harr; ///< pointer to array of elements in heap
int capacity; ///< maximum possible size of min heap
int heap_size; ///< Current number of elements in min heap
public:
// Constructor
/** Constructor
* \param[in] capacity initial heap capacity
*/
MinHeap(int capacity);
// to heapify a subtree with the root at given index
/** to heapify a subtree with the root at given index
*/
void MinHeapify(int);
int parent(int i) { return (i - 1) / 2; }
// to get index of left child of node at index i
/** to get index of left child of node at index i */
int left(int i) { return (2 * i + 1); }
// to get index of right child of node at index i
/** to get index of right child of node at index i */
int right(int i) { return (2 * i + 2); }
// to extract the root which is the minimum element
/** to extract the root which is the minimum element */
int extractMin();
// Decreases key value of key at index i to new_val
/** Decreases key value of key at index i to new_val */
void decreaseKey(int i, int new_val);
// Returns the minimum key (key at root) from min heap
/** Returns the minimum key (key at root) from min heap */
int getMin() { return harr[0]; }
// Deletes a key stored at index i
/** Deletes a key stored at index i */
void deleteKey(int i);
// Inserts a new key 'k'
/** Inserts a new key 'k' */
void insertKey(int k);
};
// Constructor: Builds a heap from a given array a[] of given size
/** Constructor: Builds a heap from a given array a[] of given size */
MinHeap::MinHeap(int cap) {
heap_size = 0;
capacity = cap;
@@ -52,7 +56,7 @@ MinHeap::MinHeap(int cap) {
// Inserts a new key 'k'
void MinHeap::insertKey(int k) {
if (heap_size == capacity) {
cout << "\nOverflow: Could not insertKey\n";
std::cout << "\nOverflow: Could not insertKey\n";
return;
}
@@ -63,17 +67,18 @@ void MinHeap::insertKey(int k) {
// Fix the min heap property if it is violated
while (i != 0 && harr[parent(i)] > harr[i]) {
swap(&harr[i], &harr[parent(i)]);
std::swap(harr[i], harr[parent(i)]);
i = parent(i);
}
}
// Decreases value of key at index 'i' to new_val. It is assumed that
// new_val is smaller than harr[i].
/** Decreases value of key at index 'i' to new_val. It is assumed that new_val
* is smaller than harr[i].
*/
void MinHeap::decreaseKey(int i, int new_val) {
harr[i] = new_val;
while (i != 0 && harr[parent(i)] > harr[i]) {
swap(&harr[i], &harr[parent(i)]);
std::swap(harr[i], harr[parent(i)]);
i = parent(i);
}
}
@@ -96,15 +101,17 @@ int MinHeap::extractMin() {
return root;
}
// This function deletes key at index i. It first reduced value to minus
// infinite, then calls extractMin()
/** This function deletes key at index i. It first reduced value to minus
* infinite, then calls extractMin()
*/
void MinHeap::deleteKey(int i) {
decreaseKey(i, INT_MIN);
extractMin();
}
// A recursive method to heapify a subtree with the root at given index
// This method assumes that the subtrees are already heapified
/** A recursive method to heapify a subtree with the root at given index
* This method assumes that the subtrees are already heapified
*/
void MinHeap::MinHeapify(int i) {
int l = left(i);
int r = right(i);
@@ -114,18 +121,11 @@ void MinHeap::MinHeapify(int i) {
if (r < heap_size && harr[r] < harr[smallest])
smallest = r;
if (smallest != i) {
swap(&harr[i], &harr[smallest]);
std::swap(harr[i], harr[smallest]);
MinHeapify(smallest);
}
}
// A utility function to swap two elements
void swap(int *x, int *y) {
int temp = *x;
*x = *y;
*y = temp;
}
// Driver program to test above functions
int main() {
MinHeap h(11);
@@ -136,9 +136,9 @@ int main() {
h.insertKey(5);
h.insertKey(4);
h.insertKey(45);
cout << h.extractMin() << " ";
cout << h.getMin() << " ";
std::cout << h.extractMin() << " ";
std::cout << h.getMin() << " ";
h.decreaseKey(2, 1);
cout << h.getMin();
std::cout << h.getMin();
return 0;
}