add heap data structure

Author: Aram-Vn

Data_structures/heap/.clang-format

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+Language: Cpp
+BasedOnStyle: Microsoft
+AlignTrailingComments: true
+BreakBeforeBraces: Custom
+BraceWrapping:
+    AfterEnum: true
+    AfterStruct: true
+    AfterClass: true
+    AfterFunction: true
+    AfterUnion: true
+    AfterExternBlock: false
+    BeforeCatch: true
+    BeforeElse: true
+    BeforeLambdaBody: true
+    BeforeWhile: false
+    AfterNamespace: false
+    SplitEmptyFunction: true
+IndentWidth: 4
+KeepEmptyLinesAtTheStartOfBlocks: false
+PointerBindsToType: false
+SpacesBeforeTrailingComments: 1
+TabWidth: 4
+UseTab: Never
+IndentCaseLabels: true
+NamespaceIndentation: All
+AccessModifierOffset: -4
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: Consecutive
+AlignConsecutiveMacros:
+    Enabled: true
+    AcrossEmptyLines: true
+    AcrossComments: false
+AllowShortCaseLabelsOnASingleLine: true
+AlignEscapedNewlines: Right
+AllowShortBlocksOnASingleLine: Always
+AllowShortEnumsOnASingleLine: false
+AlignConsecutiveDeclarations: true
+AlwaysBreakTemplateDeclarations: true
+Cpp11BracedListStyle: false
+PackConstructorInitializers: Never
+AllowShortFunctionsOnASingleLine: Empty
+ReflowComments: true
+PenaltyBreakComment: 0
+PenaltyBreakOpenParenthesis: 1

Data_structures/heap/.gitignore

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+.cache
+build/

Data_structures/heap/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.10)
+
+project(heap)
+
+add_executable(heap main.cpp)
+
+target_include_directories(heap PRIVATE 
+        ${CMAKE_CURRENT_SOURCE_DIR}/headers
+        ${CMAKE_CURRENT_SOURCE_DIR}/src )

Data_structures/heap/headers/heap.h

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+#ifndef THEAP_H
+#define THEAP_H
+
+#include <cstddef>
+#include <functional>
+#include <iostream>
+#include <vector>
+
+namespace my {
+    template <typename T, typename Cmp = std::less<T>>
+    class Heap
+    {
+    public:
+        ~Heap() = default;
+        Heap(std::vector<T> &input, const Cmp &cmp = Cmp());
+
+        template <typename RandomAccessIterator>
+        Heap(RandomAccessIterator first, RandomAccessIterator last);
+
+    public:
+        size_t   parent(size_t ind);
+        size_t   left(size_t ind);
+        size_t   right(size_t i);
+        void     push(const T &val);
+        void     pop();
+        const T &top();
+
+    private:
+        void make_heap();
+        void heapify_down(size_t ind);
+
+    public:
+        void print();
+
+    private:
+        std::vector<T> m_heap;
+        size_t         m_size;
+        Cmp            m_cmp;
+    };
+
+#include "../src/heap.hpp"
+
+} // namespace my
+
+#endif // THEAP_H

Data_structures/heap/main.cpp

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+#include <heap.h>
+#include <vector>
+
+int main()
+{
+    std::vector<int> vec = { 3, 2, 4, 1, 5, 9 };
+    my::Heap<int>    min(vec);
+    min.print();
+
+    my::Heap<int, std::greater<int>> max (vec);
+    max.print();
+
+    my::Heap<int> h(vec.begin() + 3, vec.end());
+    h.print();
+}

Data_structures/heap/src/heap.hpp

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+template <typename T, typename Cmp>
+my::Heap<T, Cmp>::Heap(std::vector<T> &input, const Cmp &cmp)
+    : m_heap(input),
+      m_size(input.size()),
+      m_cmp(cmp)
+{
+    make_heap();
+}
+
+template <typename T, typename Cmp>
+template <typename RandomAccessIterator>
+my::Heap<T, Cmp>::Heap(RandomAccessIterator first, RandomAccessIterator last)
+    : m_heap(first, last),
+      m_size(last - first),
+      m_cmp()
+{
+    make_heap();
+}
+
+template <typename T, typename Cmp>
+void my::Heap<T, Cmp>::make_heap()
+{
+    for (int i = (m_size / 2) - 1; i >= 0; --i)
+    {
+        heapify_down(i);
+    }
+}
+
+template <typename T, typename Cmp>
+size_t Heap<T, Cmp>::parent(size_t ind)
+{
+    return (ind - 1) / 2;
+}
+
+template <typename T, typename Cmp>
+size_t my::Heap<T, Cmp>::left(size_t ind)
+{
+    return 2 * ind + 1;
+}
+
+template <typename T, typename Cmp>
+size_t my::Heap<T, Cmp>::right(size_t ind)
+{
+    return 2 * ind + 2;
+}
+
+template <typename T, typename Cmp>
+void my::Heap<T, Cmp>::heapify_down(size_t ind)
+{
+    size_t largest = ind;
+    size_t l       = left(ind);
+    size_t r       = right(ind);
+
+    if (l < m_size && m_cmp(m_heap[l], m_heap[largest]))
+        largest = l;
+
+    if (r < m_size && m_cmp(m_heap[r], m_heap[largest]))
+        largest = r;
+
+    if (largest != ind)
+    {
+        std::swap(m_heap[ind], m_heap[largest]);
+        heapify_down(largest);
+    }
+}
+
+template <typename T, typename Cmp>
+void my::Heap<T, Cmp>::print()
+{
+    for (int i = 0; i < m_size; ++i)
+    {
+        std::cout << m_heap[i] << " ";
+    }
+    std::cout << std::endl;
+}