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max_heap.cpp
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137 lines (109 loc) · 3.52 KB
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#include <iostream>
#include <vector>
#include <climits>
class MaxHeap
{
public:
MaxHeap(std::vector<int> &v) {
_size = v.size();
_heap = v;
for (int i = _size / 2 +1 ; i > -1 ; --i)
SiftDown(i);
_maxSize = _heap.capacity();
}
~MaxHeap() {}
int Parent(int i) { return (i - 1) / 2; }
int LeftChild(int i) { return 2 * i + 1; }
int RightChild(int i) { return 2 * i + 2; }
int size() { return _size; }
int maxSize() { return _maxSize; }
void SiftUp(int i) {
while (i > 0 && _heap[Parent(i)] < _heap[i])
{
std::swap(_heap[Parent(i)], _heap[i]);
i = Parent(i);
}
}
void SiftDown(int i) {
int maxIndex = i;
int l = LeftChild(i);
if (l < _size && _heap[l] > _heap[maxIndex])
maxIndex = l;
int r = RightChild(i);
if (r < _size && _heap[r] > _heap[maxIndex])
maxIndex = r;
if (i != maxIndex)
{
std::swap(_heap[i], _heap[maxIndex]);
SiftDown(maxIndex);
}
}
void Insert(int p) {
if (_size == _maxSize) {
std::cout << "Max size!";
return;
}
++_size;
_heap[_size - 1] = p;
SiftUp(_size -1);
}
int ExtractMax() {
int result = _heap[0];
_heap[0] = _heap[_size -1];
--_size;
SiftDown(0);
return result;
}
void Remove(int i) {
_heap[i] = INT_MAX;
SiftUp(i);
ExtractMax();
}
void ChangePriority(int i, int p) {
int oldp = _heap[i];
_heap[i] = p;
if (p > oldp)
SiftUp(i);
else
SiftDown(i);
}
std::vector<int> const & heap() { return _heap; }
private:
std::vector<int> _heap;
int _size;
int _maxSize;
};
int main(void) {
std::vector<int> v = {7, 11, 29, 12, 42, 18, 13, 18, 14};
for (int i = 0; i < v.size(); ++i)
std::cout << v[i] << " ";
std::cout << std::endl;
MaxHeap h(v);
for (int i = 0; i < h.size(); ++i)
std::cout << h.heap()[i] << " ";
std::cout << std::endl;
std::cout << "\t\t\t" <<h.heap()[0] << std::endl;
std::cout << "\t\t" << h.heap()[h.LeftChild(0)] << "\t\t" << h.heap()[h.RightChild(0)] << std::endl;
std::cout << "\t"<< h.heap()[h.LeftChild(h.LeftChild(0))] << "\t" << h.heap()[h.RightChild(h.LeftChild(0))] << "\t\t" <<
h.heap()[h.LeftChild(h.RightChild(0))] << "\t" << h.heap()[h.RightChild(h.RightChild(0))] << std::endl;
std::cout << h.heap()[h.LeftChild(h.LeftChild(h.LeftChild(0)))] << "\t" << h.heap()[h.RightChild(h.LeftChild(h.LeftChild(0)))] << std::endl<< std::endl;
h.ExtractMax();
for (int i = 0; i < h.size(); ++i)
std::cout << h.heap()[i] << " ";
std::cout << std::endl;
std::cout << "\t\t\t" <<h.heap()[0] << std::endl;
std::cout << "\t\t" << h.heap()[h.LeftChild(0)] << "\t\t" << h.heap()[h.RightChild(0)] << std::endl;
std::cout << "\t"<< h.heap()[h.LeftChild(h.LeftChild(0))] << "\t" << h.heap()[h.RightChild(h.LeftChild(0))] << "\t\t" <<
h.heap()[h.LeftChild(h.RightChild(0))] << "\t" << h.heap()[h.RightChild(h.RightChild(0))] << std::endl;
std::cout << h.heap()[h.LeftChild(h.LeftChild(h.LeftChild(0)))] << std::endl<< std::endl;
h.Insert(58);
for (int i = 0; i < h.size(); ++i)
std::cout << h.heap()[i] << " ";
std::cout << std::endl;
std::cout << "\t\t\t" <<h.heap()[0] << std::endl;
std::cout << "\t\t" << h.heap()[h.LeftChild(0)] << "\t\t" << h.heap()[h.RightChild(0)] << std::endl;
std::cout << "\t"<< h.heap()[h.LeftChild(h.LeftChild(0))] << "\t" << h.heap()[h.RightChild(h.LeftChild(0))] << "\t\t" <<
h.heap()[h.LeftChild(h.RightChild(0))] << "\t" << h.heap()[h.RightChild(h.RightChild(0))] << std::endl;
std::cout << h.heap()[h.LeftChild(h.LeftChild(h.LeftChild(0)))] << "\t" << h.heap()[h.RightChild(h.LeftChild(h.LeftChild(0)))] << std::endl<< std::endl;
return 0;
}