算法导论 最优搜索树

算法参考算法导论第二版——最优搜索树

#include<iostream>
#define EType int
#define MAX numeric_limits<double>::max()
using namespace std;
void Construct_Optimal_BST(int **root,int i,int j,bool flag);
void OPTIMAL_BST(double p[],double q[], int n)
{
 double **e,**w;
 int **root;
 e = new double*[n+2];
 w = new double*[n+2];
 e[0] = new double[(n+2)*(n+2)];
 w[0] = new double[(n+2)*(n+2)];
 root = new int*[n+1];
 root[0] = new int[(n+1)*(n+1)];
 for(int i = 1; i < n+2; ++i)
 {
  e[i][i-1] = q[i-1];
  w[i][i-1] = q[i-1];
  e[0][i-1] = 0;
  w[0][i-1] = 0;
 }
 for(int i = 1; i< (n+2); ++i)
  for(int j = 1; j< (n+2); ++j)
   root[i][j] = 0;
 for(int l = 1; l<=n; ++l)
  for(int i = 1; i <= n-l+1; )
  {
   int j = i+l-1;
   e[i][j] = MAX;
   w[i][j] = w[i][j-1] + p[j] + q[j];
   for(int r = i; r<= j; ++r)
   {
    int t = e[i][r-1] + e[r+1][j] + w[i][j];
    if(t<e[i][j])
    {
     e[i][j] = t;
     root[i][j] = r;
    }
   }

  }
 Construct_Optimal_BST(root,1,n,false);
}
void Construct_Optimal_BST(int **root,int i,int j,bool flag)
{
 if(flag==0)
 {
  cout<<"k"<<root[i][j]<<" 是根"<<endl;
  flag=1;
 }
 int r=root[i][j];
 //如果左子树是叶子
 if(r-1<i)
 {
  cout<<"d"<<r-1<<" is the left child of "<<"K"<<r<<endl;
 }
 //如果左子树不是叶子
 else
 {
  cout<<"k"<<root[i][r-1]<<" is the left child of "<<"K"<<r<<endl;
  Construct_Optimal_BST(root,i,r-1,1);
 }
 //如果右子树是叶子
 if(r>=j)
 {
  cout<<"d"<<j<<" is the right child of "<<"K"<<r<<endl;
 }
 //如果右子树不是叶子
 else
 {
  cout<<"k"<<root[r+1][j]<<" is the right child of "<<"K"<<r<<endl;
  Construct_Optimal_BST(root,r+1,j,1);
 }
}