算法导论6.5-9,K个有序链表合并 nlgn

#include <vector>
#include <list>
#include <iostream>
#include <limits.h>

using namespace std;


template<typename Comparable>
class minKList
{
public:
	explicit minKList(int capacity=100)
	:array(capacity+1),currentSize(0)
	{ }

	explicit minKList(const vector<list<Comparable>> &items)
	:array(items.size()+10),currentSize(items.size())
	{
		vec=items;
		for(int i=0;i<vec.size();++i)
			array[i+1]=&vec[i];
		buildMinHeap();
	}

	void merge()
	{
		int num=0;
		for(int i=1;i<=currentSize;i++)
			num+=array[i]->size();
	
		for(int i=0;i<num;i++)
		{
			minHeapIfy(1);
			ret.push_back(array[1]->front());
			array[1]->pop_front();
			if(array[1]->empty())
				array[1]->push_back(INT_MAX);
		}
	}

	void mergePrint()
	{
		for(auto v:ret)
			cout<<v<<" ";
		cout<<endl;
	}


private:
	int currentSize;
	vector<list<Comparable>> vec;
	vector<list<Comparable>*> array;

	vector<Comparable> ret;


	void buildMinHeap()
	{
		for(int i=currentSize/2;i!=0;i--)
			minHeapIfy(i);
	}

	void minHeapIfy(int i)
	{
		int child;
		list<Comparable>*	tmp;
		tmp=array[i]; 
		for(;i*2<=currentSize;i=child)
		{
			child=i*2;
			if(child!=currentSize&&array[child+1]->front()<array[child]->front())
				++child;

			if(array[child]->front()<tmp->front())
				std::swap(array[i],array[child]);

			else
				break;
		}
	}

};


int main()
{
	vector<list<int>> vec;
	list<int> list1{5,10,15,20};
	list<int> list2{4,8,12,16};
	list<int> list3{1,18,25,99};
	
	vec.push_back(list1);
	vec.push_back(list2);
	vec.push_back(list3);
	
	minKList<int> heap{vec};
	heap.merge();
	heap.mergePrint();

}