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#include <iostream>
#include <tuple>
#include <vector>
#include <queue>
#include <functional>
#include <string>
#include <memory>
using namespace std;
class binarySearchTree
{
public:
struct treeNode
{
char data;
shared_ptr<treeNode> left, right;
};
shared_ptr<treeNode> root;
void setRoot(char a)
{
root = make_shared<treeNode>();
(*root).data = a;
}
void mergeSubTrees(const shared_ptr<binarySearchTree>& nodeA, const shared_ptr<binarySearchTree>& nodeB)
{
root = make_shared<treeNode>();
(*root).left = (*nodeA).root; (*root).right = (*nodeB).root;
}
void inOrder(shared_ptr<treeNode> tNodeCurr, vector<tuple<char, string>>& huffmanCodes, string& tempStr)
{
if (tNodeCurr)
{
if ((*tNodeCurr).data) huffmanCodes.push_back(make_tuple((*tNodeCurr).data, tempStr));
if ((*tNodeCurr).left)
{
tempStr += "0";
inOrder((*tNodeCurr).left, huffmanCodes, tempStr);
tempStr.pop_back();
}
if ((*tNodeCurr).right)
{
tempStr += "1";
inOrder((*tNodeCurr).right, huffmanCodes, tempStr);
tempStr.pop_back();
}
}
else return;
}
};
vector<tuple<char, string>> generateHuffmanCodes(const vector<tuple<int, char>>& characterList)
{
vector<tuple<char, string>> huffmanCodes;
if (characterList.size() > 1)
{
int i, j, queueChoice;
string tempStr;
priority_queue<tuple<int, shared_ptr<binarySearchTree>>, vector<tuple<int, shared_ptr<binarySearchTree>>>, greater<tuple<int, shared_ptr<binarySearchTree>>> > characterListPQ1, characterListPQ2;
shared_ptr<binarySearchTree> binarySearchTreePtr1 = make_shared<binarySearchTree>(), binarySearchTreePtr2;
auto characterListIterator = characterList.cbegin();
for (; characterListIterator != characterList.end(); ++characterListIterator)
{
(*binarySearchTreePtr1).setRoot(get <1>(*characterListIterator));
characterListPQ1.push(make_tuple(get <0>(*characterListIterator), make_shared<binarySearchTree>(*binarySearchTreePtr1)));
}
binarySearchTreePtr1 = NULL;
while (characterListPQ1.size() + characterListPQ2.size() > 1)
{
if (characterListPQ1.size() == 0)
{
i = get <0>(characterListPQ2.top());
binarySearchTreePtr1 = get <1>(characterListPQ2.top());
characterListPQ2.pop();
binarySearchTreePtr2 = get <1>(characterListPQ2.top());
shared_ptr<binarySearchTree> binaryMergedSearchTreePtr = make_shared<binarySearchTree>();
(*binaryMergedSearchTreePtr).mergeSubTrees(binarySearchTreePtr1, binarySearchTreePtr2);
characterListPQ1.push(make_tuple(i + get <0>(characterListPQ2.top()), binaryMergedSearchTreePtr));
characterListPQ2.pop();
}
else if (characterListPQ2.size() == 0)
{
i = get <0>(characterListPQ1.top());
binarySearchTreePtr1 = get <1>(characterListPQ1.top());
characterListPQ1.pop();
binarySearchTreePtr2 = get <1>(characterListPQ1.top());
shared_ptr<binarySearchTree> binaryMergedSearchTreePtr = make_shared<binarySearchTree>();
(*binaryMergedSearchTreePtr).mergeSubTrees(binarySearchTreePtr1, binarySearchTreePtr2);
characterListPQ2.push(make_tuple(i + get <0>(characterListPQ1.top()), binaryMergedSearchTreePtr));
characterListPQ1.pop();
}
else
{
if (get <0>(characterListPQ1.top()) < get <0>(characterListPQ2.top()))
{
i = get <0>(characterListPQ1.top());
binarySearchTreePtr1 = get <1>(characterListPQ1.top());
characterListPQ1.pop();
}
else
{
i = get <0>(characterListPQ2.top());
binarySearchTreePtr1 = get <1>(characterListPQ2.top());
characterListPQ2.pop();
}
if (get <0>(characterListPQ1.top()) < get <0>(characterListPQ2.top()))
{
j = get <0>(characterListPQ1.top());
binarySearchTreePtr2 = get <1>(characterListPQ1.top());
characterListPQ1.pop();
queueChoice = 1;
}
else
{
j = get <0>(characterListPQ2.top());
binarySearchTreePtr2 = get <1>(characterListPQ2.top());
characterListPQ2.pop();
queueChoice = 2;
}
shared_ptr<binarySearchTree> binaryMergedSearchTreePtr = make_shared<binarySearchTree>();
(*binaryMergedSearchTreePtr).mergeSubTrees(binarySearchTreePtr1, binarySearchTreePtr2);
if (queueChoice == 1) characterListPQ2.push(make_tuple(i + j, binaryMergedSearchTreePtr));
else characterListPQ2.push(make_tuple(i + j, binaryMergedSearchTreePtr));
}
}
if (characterListPQ1.size() == 1) binarySearchTreePtr1 = get <1>(characterListPQ1.top());
else binarySearchTreePtr1 = get <1>(characterListPQ2.top());
(*binarySearchTreePtr1).inOrder((*binarySearchTreePtr1).root, huffmanCodes, tempStr);
}
return huffmanCodes;
}
int main()
{
vector<tuple<int, char>> characterList(6);
characterList[0] = make_tuple(3, 'A');
characterList[1] = make_tuple(2, 'B');
characterList[2] = make_tuple(6, 'C');
characterList[3] = make_tuple(8, 'D');
characterList[4] = make_tuple(2, 'E');
characterList[5] = make_tuple(6, 'F');
sort(characterList.begin(), characterList.end(), less<tuple<int, char>>());
auto huffmanCodes = generateHuffmanCodes(characterList);
return 0;
}
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