BST optimal binary search tree (Java version)

The content was last summer, but it never came true.

In fact, it is the interval DP, to find a sequence to form a binary tree, the sequence of sequential traversal.

The core is the same as the rest of the interval DP, which enumerates the intermediate values. Then the probability of the whole interval is summed up after enumeration, because it is equivalent to a deeper layer.

Java code, test data attached

Import Java.util.arrays;import Java.util.scanner;public class Main {/** * input P: Access probability array; 0,1,.... n is a well-ordered key value * Output A=new float[ N][n]: Optimal time Matrix * output R=new int[n][n]: root node Matrix * @param p * @param A * @param R */static void Optimalbst (double[] p, double[][] A, int[][] R) {int n = p.length; Arrays.sort (P); for (int i = 0; i < n; i++) {a[i][i] = P[i]; R[i][i] = i;  The root is itself}for (int len = 1, len < n; len++) {for (int st = 0; St + len < n; st++) {int ed = st + Len;int  root = st;double min = double.max_value;for (int k = st; k <= ed; k++) {double tmp;if (k = = st) tmp = a[k + 1][ed];else if (k = = ed) tmp = A[st][k-1];elsetmp = A[k + 1][ed] + a[st][k-1];if (min > tmp) {min = Tmp;root = k;}} R[st][ed] = root; A[st][ed] = min;for (int i = st; I <= ed; i++) a[st][ed] + = P[i];}}} public static void print (int st,int ed,int [] R) {if (st==ed) {System.out.print (r[st][ed]); return;} System.out.print ("(");p rint (st,r[st][ed]-1,r); System.out.print (")"); System.out.print (r[st][ed]); System.out.prInt ("(");p rint (r[st][ed]+1,ed,r); System.out.print (")");}  public static void Main (string[] args) {//scanner input = new Scanner (system.in);d ouble [] A = new Double[5][5];int [] R = new Int[5][5];//optimalbst1 (new double [] {0.15, 0.10,0.05,0.10,0.20},a,r);//system.out.println (A[0][4]);//print ( 0,4,R); Optimalbst (new double [] {0.15, 0.10,0.05,0.10,0.20},a,r); System.out.println (a[0][4]);p rint (0,4,r);}}

BST optimal binary search tree (Java version)