算法之动态规划最优二叉树

1. package com.eshore.sweetop.dynamicprogramming;
3. public class BestBinTree {
4.     //关键字节点,p[0]为构造数据
5. //  double[] p={0,0.15,0.10,0.05,0.10,0.20};
6.     //虚拟节点
7. //  double[] q={0.05,0.10,0.05,0.05,0.05,0.10};
8.     //规模
9. //  int n=5;
10.     
11.     double[] p={0,0.04,0.06,0.08,0.02,0.10,0.12,0.14};
12.     double[] q={0.06,0.06,0.06,0.06,0.05,0.05,0.05,0.05};
13.     static int n=7;
14.     
15.     double[][] e=new double[n+2][n+1];
16.     double[][] w=new double[n+2][n+1];
17.     int[][] root=new int[n+2][n+2];
18.     
19.     public void optimalBest(){
20.         for (int i = 1; i < e.length; i++) {
21.             e[i][i-1]=q[i-1];
22.             w[i][i-1]=q[i-1];
23.         }
25.         
26.         for (int l = 1; l < n+1; l++) {
27.             for (int i = 1; i <= n-l+1; i++) {
28.                 int j=i+l-1;
29.                 e[i][j]=Double.MAX_VALUE;
30.                 w[i][j]=w[i][j-1]+p[j]+q[j];
31.                 for (int r = i; r <= j; r++) {
32.                     double t=e[i][r-1]+e[r+1][j]+w[i][j];
33.                     if(t<e[i][j]){
34.                         e[i][j]=t;
35.                         System.out.println(r);
36.                         root[i][j]=r;
37.                     }
38.                 }
39.             }   
40.         }
41. //      BestBinTree.display(w);
42. //      BestBinTree.display(e); 
43.         BestBinTree.display(root);
44.         
45.         BestBinTree.viewTree(root);
46.     }
47.     
48.     public static void display(double[][] a){
49.         for (int i = 1; i < a.length; i++) {
50.             for (int j = 1; j < a[0].length; j++) {
51.                 System.out.print(String.format("%.2f", a[i][j])+"/t");
52.             }
53.             System.out.println();
54.         }
55.     }
56.     
57.     public static void display(int[][] a){
58.         for (int i = 1; i < a.length; i++) {
59.             for (int j = 1; j < a[0].length; j++) {
60.                 if(i<=j)
61.                 System.out.print(a[i][j]+" ");
62.             }
63.             System.out.println();
64.         }
65.     }
66.     
67.     public static void viewTree(int[][] a){
68.         System.out.println("根是k"+a[1][n]);
69.         view(a,a[1][n],1,n);
70. //      System.out.println(a[6][7]);
71.     }
72.     
73.     public static void view(int[][] a,int root,int i,int j){
74.         if(a[i][root-1]==0){
75.             System.out.println("k"+root+"左孩子是d"+(root-1));
76.         }else{
77.             System.out.println("k"+root+"左孩子是k"+a[i][root-1]);  
78.             view(a,a[i][root-1],i,root-1);
79.         }
80.         if(a[root+1][j]==0){
81.             System.out.println("k"+root+"右孩子是d"+root);
82.         }else{
83.             System.out.println("k"+root+"右孩子是k"+a[root+1][j]);
84.             view(a,a[root+1][j],root+1,j);
85.         }
86.     }
87.     
88.     
89.     public static void main(String[] args) {
90.         BestBinTree bbt=new BestBinTree();
91.         bbt.optimalBest();
92.     }
93.     
94. }