How Many Trees?

本文介绍了一段使用Java实现的代码,用于计算卡特兰数。通过输入一个数n,程序输出了n个数构成的不同形状的二叉树表示,即计算了S1=C(2*n,n)/(n+1),并利用Java的大数类处理数据过大的问题。

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 1 import java.util.*;
 2 import java.math.*;
 3 public class Main
 4 {
 5     public static void main(String []args)
 6     {
 7         Scanner cin=new Scanner(System.in);
 8         int i,n;
 9         while(cin.hasNext())
10         {    
11             n=cin.nextInt();
12             BigInteger s1 = BigInteger.valueOf(1);
13             BigInteger s2 = BigInteger.valueOf(1);
14             for(i=1;i<=n;i++)
15             {
16                 s1=s1.multiply(BigInteger.valueOf(2*n-i+1));
17                 s2=s2.multiply(BigInteger.valueOf(i));
18             }
19             s1=s1.divide(BigInteger.valueOf(n+1));
20             System.out.println(s1.divide(s2));    
21         }
22     }
23 }

这个题目意思是指给出一个数n,输出n 个数构成的不同形状的二叉树,表示使用公式,利用卡特兰数的推导公式,

则有:S1=C(2*n,n)/(n+1).

表示数据过于庞大,所以选择了用Java的大数类来计算~~

转载于:https://www.cnblogs.com/ouyangduoduo/archive/2012/06/21/2558050.html

R R version 4.2.2 (2022-10-31) -- "Innocent and Trusting" Copyright (C) 2022 The R Foundation for Statistical Computing Platform: x86_64-conda-linux-gnu (64-bit) R is free software and comes with ABSOLUTELY NO WARRANTY. You are welcome to redistribute it under certain conditions. Type 'license()' or 'licence()' for distribution details. Natural language support but running in an English locale R is a collaborative project with many contributors.Type 'contributors()' for more information and 'citation()' on how to cite R or R packages in publications. Type 'demo()' for some demos, 'help()' for on-line help, or 'help.start()' for an HTML browser interface to help. Type 'q()' to quit R. library(ape) setwd("/ifs1/User/dengwei/NTF_data/7.14/rooted_species_tree") species_tree <- read.tree("species_tree.treefile")> compare_trees <- function(gene_tree_file, species_tree) { gene_tree <- read.tree(gene_tree_file) diff_count <- comparePhylo(gene_tree, species_tree, force.rooted = TRUE) return(diff_count) } batch_compare_trees <- function(gene_tree_folder, species_tree) { gene_tree_files <- list.files(path = gene_tree_folder, pattern = ".treefile", full.names = TRUE) diff_counts <- data.frame(Gene_Tree_File = gene_tree_files, Diff_Count = numeric(length(gene_tree_files)), stringsAsFactors = FALSE) for (i in seq_along(gene_tree_files)) { gene_tree_file <- gene_tree_files[i] diff_counts$Diff_Count[i] <- compare_trees(gene_tree_file, species_tree) } return(diff_counts) } gene_tree_folder <- "/ifs1/User/dengwei/NTF_data/7.14/rooted_gene_tree" diff_counts <- batch_compare_trees(gene_tree_folder, species_tree) Error in if (n1 == n2) paste("Both trees have the same number of tips:", : the condition has length > 1
07-15
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