矩阵连乘算法 c++.doc

#include <iostream>
#include <iomanip>
using namespace std;

class MatrixChain
{
public:
MatrixChain(int *q,int mSize);
~MatrixChain();
int MChain();
void print();
private:
void print(int i,int j);
int *p;
int **m,**s;
int n;
};

void MatrixChain::print(int i,int j)
{
if(i==j)
{
cout<<char('A'+i);
return;
}

if(i<s[i][j])
cout<<'(';
print(i,s[i][j]);
if(i<s[i][j])
cout<<')';

if(j>s[i][j]+1)
cout<<'(';
print(s[i][j]+1,j);
if(j>s[i][j]+1)
cout<<')';
}

void MatrixChain::print()
{
//cout<<'(';
print(0,n-1);
//cout<<')';
}

int MatrixChain::MChain()
{
for(int i=0;i<n;i++)
{
m[i][i]=0;
s[i][i]=0;
}
for(int r=2;r<=n;r++)
{
for(int i=0;i<=n-r;i++)
{
int temp=0;
int j=i+r-1;
s[i][j]=i;
m[i][j]=m[i+1][j]+p[i]*p[i+1]*p[j+1];
for(int k=i+1;k<j;k++)
{
temp=m[i][k]+m[k+1][j]+p[i]*p[k+1]*p[j+1];
if(temp<m[i][j])
{
m[i][j]=temp;
s[i][j]=k;
}
}
}
}
return m[0][n-1];
}

MatrixChain::MatrixChain(int *q, int mSize)
{
n=mSize;
p=new int [n+1];
for(int i=0;i<n+1;i++)
p[i]=q[i];
m=new int *[n];
s=new int *[n];
for(int i=0;i<n;i++)
{
m[i]=new int[n];
s[i]=new int[n];
}
}

MatrixChain::~MatrixChain()
{
delete []p;
for(int i=0;i<n;i++)
{
delete []m[i];
delete []s[i];
}
delete []m;
delete []s;
}

void main()
{
int p[7]={30,35,15,5,10,20,25};
MatrixChain mc(p,6);
cout<<mc.MChain()<<endl;
mc.print();
}