#include <iostream>
#include <initializer_list>
#include <utility>
#include <typeinfo>
#include <vector>
#include <iterator>
enum MValue:unsigned long { MAXVALUE=1000000 };
template<typename T=long>
class MatrixChainOrder{ //矩阵链最优顺序计算.
private:
std::vector<std::vector<T>> M;
std::vector<std::vector<T>> S;
std::vector<T> chains;
public:
template<typename U=long>
MatrixChainOrder(const std::initializer_list<U>& il)noexcept(true); //([&theIl]()->bool { (theIl.size()==0)?true:false});
~MatrixChainOrder()noexcept(true);
void chainOrder();
void print();
};
template<typename T>
template<typename U>
MatrixChainOrder<T>::MatrixChainOrder(const std::initializer_list<U>& il)noexcept(true)
:chains(il)
{
int temp=chains.size();
std::vector<T> tempVec(temp); //初始化一个有temp个元素的vector;
for(int i=0; i<temp; ++i){
this->M.push_back(tempVec);
this->S.push_back(tempVec);
}
}
template<typename T>
MatrixChainOrder<T>::~MatrixChainOrder()noexcept(true)
{
int temp=M.size();
for(int i=0; i<temp; ++temp){
M[i].clear();
S[i].clear();
}
M.clear();
S.clear();
std::cout<<"destroy it"<<std::endl;
}
template<typename T>
void MatrixChainOrder<T>::chainOrder()
{
int n=this->chains.size();//n是矩阵链摊开后的大小.例如:A(x,y),A1(x1,y1),那么chains={x*y*x1*y1};
/*
假设矩阵Ai........Aj,之间存在最优相乘代价.最优分割点k且 i<=k<j;
M[i][j]=M[i][k]+M[k+1][j]+x*x1*y1;
*/
int j;
int q;//a temporary value.
if(typeid(T)==typeid(long int) || typeid(T)==typeid(double)){
std::cout<<"success to enter"<<std::endl;
for(int i=0; i<n; ++i){
this->M[i][i]=0;//M[1][1], M[2][2], M[3][3]; M相当于计算chains中i-i所需要的代价.
}
for(int l=2; l<n; ++l){//当chains内至少有两个元素的时候.假设n=6;
for(int i=0; i<n-l+1; ++i){//l=2,i=5,4,3...1;
j=i+l-1;//j得到的是6,5,4,3,2,1....
M[i][j]=MAXVALUE;
for(int k=i; i<j; ++i){//k=0,1,2,...5; 2...4; ....
q=M[i][k]+M[k+1][j]+chains[i-1]*chains[k]*chains[j];//计算从i-j的最优代价.
if(q < M[i][j]){
M[i][j]=q;
S[i][j]=k;//记录最佳分割点.
}
}
}
}
}
}
template<typename T>
void MatrixChainOrder<T>::print()
{
std::ostream_iterator<T> out(std::cout, " ");
std::cout<<"print M:"<<std::endl;
if(M.empty()){
std::cout<<"chains are less than 1"<<std::endl;
}else{
for(auto tempM: this->M){
for(auto tempT:tempM){
*(out++)=tempT;
}
}
std::cout<<"\n"<<"print S:"<<std::endl;
for(auto tempS: this->S){
for(auto tempT:tempS){
*(out++)=tempT;
}
}
}
}
int main()
{
MatrixChainOrder<> myChains( {30l, 35l, 35l, 15l, 15l, 5l, 5l, 10l, 10l, 20l, 20l, 25l} );
myChains.chainOrder();
myChains.print();
return 0;
}
