Saturday, March 28, 2015

Sort a set of strings by each string's last character, solution 2

Here's another solution to the same problem, this time I am not using a comparator. Instead, I reverse each element, save it in a new TreeSet which keeps elements in sorted order, then instantiate a new LinkedHashSet which maintains an insertion order, reverse the strings again to the way there were. What I noticed doing this problem is that this solution is faster with larger sample size than solution with comparator. That's a surprising revelation. Also, using StringBuilder to reverse a string is a lot faster than reversing character by character.
 package com.ervits;  
 import java.util.Arrays;  
 import java.util.HashSet;  
 import java.util.LinkedHashSet;  
 import java.util.Objects;  
 import java.util.Set;  
 import java.util.TreeSet;  
 /**  
  *  
  * @author Artem  
  * @created Mar 27, 2015 2:15:49 PM  
  *  
  * Project SetSorter  
  *  
  */  
 public class SetSorterWithReverseString {  
   public static void main(String[] args) {  
     long start = System.currentTimeMillis();  
     Set<String> unsorted = new HashSet<>();  
     unsorted.addAll(Arrays.asList("Abstract", "class", "is", "a", "special",   
         "class", "in", "Java", "it", "can", "not", "be", "instantiated",   
         "and", "that's", "why", "can", "not", "be", "used", "directly",  
         "At", "first", "concept", "of", "abstraction", "abstract",   
         "class", "and", "interface", "all", "look", "useless", "to",   
         "many", "developers", "because", "you", "can", "not", "implement",   
         "any", "method", "in", "interface", "you", "can", "not", "create", "object",  
         "To", "create", "these", "etexts", "the", "Project", "expends", "considerable",  
         "efforts", "to", "identify", "transcribe", "and", "proofread", "public", "domain",  
         "Take", "the", "hue", "of", "the", "company", "you", "are", "with", "Take",   
         "characters", "as", "they", "do", "most", "things", "upon", "trust",   
         "Take", "rather", "than", "give", "the", "tone", "of", "the", "company",   
         "you", "are", "in", "Take", "nothing", "for", "granted", "upon", "the",   
         "bare", "authority", "of", "the", "author", "Taking", "up", "adventitious",   
         "proves", "their", "want", "of", "intrinsic", "merit", "Talent", "of", "hating",   
         "with", "good_breeding", "and", "loving", "with", "prudence", "Talk", "often",   
         "but", "never", "long", "Talk", "sillily", "upon", "a", "subject", "of", "other",   
         "people's", "Talk", "of", "natural", "affection", "is", "talking", "nonsense",   
         "Talking", "of", "either", "your", "own", "or", "other", "people's", "domestic",   
         "affairs", "Tell", "me", "whom", "you", "live", "with", "and", "I", "will",   
         "tell", "you", "who", "you", "are", "Tell", "stories", "very", "seldom", "The",   
         "longest", "life", "is", "too", "short", "for", "knowledge", "The", "present",   
         "moments", "are", "the", "only", "ones", "we", "are", "sure", "of", "The", "best",   
         "have", "something", "bad", "and", "something", "little", "The", "worst", "have",   
         "something", "good", "and", "sometimes", "something", "great", "There", "are",   
         "many", "avenues", "to", "every", "man", "They", "thought", "I", "informed",   
         "because", "I", "pleased", "them", "Thin", "veil", "of", "Modesty", "drawn",   
         "before", "Vanity", "Think", "to", "atone", "by", "zeal", "for", "their",   
         "want", "of", "merit", "and", "importance", "Think", "yourself", "less",   
         "well", "than", "you", "are", "in", "order", "to", "be", "quite", "so",   
         "Thinks", "himself", "much", "worse", "than", "he", "is", "Thoroughly",   
         "not", "superficially", "Those", "who", "remarkably", "affect", "any",   
         "one", "virtue", "Those", "whom", "you", "can", "make", "like", "themselves",   
         "better", "Three", "passions", "that", "often", "put", "honesty", "to",   
         "most", "severe", "trials", "Timidity", "and", "diffidence", "To", "be",   
         "heard", "with", "success", "you", "must", "be", "heard", "with", "pleasure",   
         "To", "be", "pleased", "one", "must", "please", "To", "govern", "mankind",   
         "one", "must", "not", "overrate", "them", "To", "seem", "to", "have", "forgotten",   
         "what", "one", "remembers", "To", "know", "people's", "real", "sentiments",   
         "I", "trust", "much", "more", "to", "my", "eyes", "To", "great", "caution",   
         "you", "can", "join", "seeming", "frankness", "and", "openness", "Too", "like",   
         "and", "too", "exact", "a", "picture", "of", "human", "nature", "Trifle", "only",   
         "with", "triflers", "and", "be", "serious", "only", "with", "the", "serious",   
         "Trifles", "that", "concern", "you", "are", "not", "trifles", "to", "me",   
         "Trifling", "parts", "with", "their", "little", "jargon", "Trite", "jokes",   
         "and", "loud", "laughter", "reduce", "him", "to", "a", "buffoon", "Truth",   
         "but", "not", "the", "whole", "truth", "must", "be", "the", "invariable",   
         "principle", "Truth", "leaves", "no", "room", "for", "compliments", "Unaffected",   
         "silence", "upon", "that", "subject", "is", "the", "only", "true", "medium",   
         "Unguarded", "frankness", "Unintelligible", "to", "his", "readers", "and",   
         "sometimes", "to", "himself", "Unopened", "because", "one", "title", "in",   
         "twenty", "has", "been", "omitted", "Unwilling", "and", "forced", "it",   
         "will", "never", "please", "Use", "palliatives", "when", "you", "contradict",   
         "Useful", "sometimes", "to", "see", "the", "things", "which", "one", "ought",   
         "to", "avoid", "Value", "of", "moments", "when", "cast", "up", "is", "immense",   
         "Vanity", "interest", "and", "absurdity", "always", "display", "Vanity", "that",   
         "source", "of", "many", "of", "our", "follies", "Warm", "and", "young", "thanks",   
         "not", "old", "and", "cold", "ones", "Water_drinkers", "can", "write", "nothing",   
         "good", "We", "love", "to", "be", "pleased", "better", "than", "to", "be",   
         "informed", "We", "have", "many", "of", "those", "useful", "prejudices", "in",   
         "this", "country", "We", "shall", "be", "feared", "if", "we", "do", "not",   
         "show", "that", "we", "fear", "Well", "dressed", "not", "finely", "dressed",   
         "What", "pleases", "you", "in", "others", "will", "in", "general", "please",   
         "them", "in", "you", "What", "displeases", "or", "pleases", "you", "in",   
         "others", "What", "you", "feel", "pleases", "you", "in", "them", "What",   
         "have", "I", "done", "to_day", "What", "is", "impossible", "and", "what",   
         "is", "only", "difficult", "Whatever", "pleases", "you", "most", "in",   
         "others", "Whatever", "is", "worth", "doing", "at", "all", "is", "worth",   
         "doing", "well", "Whatever", "one", "must", "do", "one", "should", "do",   
         "de", "bonne", "grace", "Whatever", "real", "merit", "you", "have",   
         "other", "people", "will", "discover", "When", "well", "dressed",   
         "for", "the", "day", "think", "no", "more", "of", "it", "afterward",   
         "Where", "one", "would", "gain", "people", "remember", "that", "nothing",   
         "is", "little", "Who", "takes", "warning", "by", "the", "fate", "of",   
         "others", "Wife", "very", "often", "heard", "indeed", "but", "seldom",   
         "minded", "Will", "not", "so", "much", "as", "hint", "at", "our", "follies",   
         "Will", "pay", "very", "dear", "for", "the", "quarrels", "and", "ambition",   
         "of", "a", "few", "Wish", "you", "my", "dear", "friend", "as", "many",   
         "happy", "new", "years", "as", "you", "deserve", "Wit", "may", "created",   
         "any", "admirers", "but", "makes", "few", "friends", "Witty", "without",   
         "satire", "or", "commonplace", "Woman", "like", "her", "who", "has",   
         "always", "pleased", "and", "often", "been", "pleased", "Women", "are",   
         "the", "only", "refiners", "of", "the", "merit", "of", "men", "Women",   
         "choose", "their", "favorites", "more", "by", "the", "ear", "Women",   
         "are", "all", "so", "far", "Machiavelians", "Words", "are", "the",   
         "dress", "of", "thoughts", "World", "is", "taken", "by", "the",   
         "outside", "of", "things", "Would", "not", "tell", "what", "she",   
         "did", "not", "know", "Wrapped", "up", "and", "absorbed", "in",   
         "their", "abstruse", "speculations", "Writing", "anything", "that",   
         "may", "deserve", "to", "be", "read", "Writing", "what", "may",   
         "deserve", "to", "be", "read", "Wrongs", "are", "often",   
         "forgiven", "but", "contempt", "never", "is", "Yielded", "commonly",   
         "without", "conviction", "You", "must", "be", "respectable", "if",   
         "you", "will", "be", "respected", "You", "had", "much", "better",   
         "hold", "your", "tongue", "than", "them", "Young", "people", "are",   
         "very", "apt", "to", "overrate", "both", "men", "and", "things",   
         "Young", "fellow", "ought", "to", "be", "wiser", "than", "he",   
         "should", "seem", "to", "be", "Young", "men", "are", "as", "apt",   
         "to", "think", "themselves", "wise", "enough", "Your", "merit",   
         "and", "your", "manners", "can", "alone", "raise", "you", "Your",   
         "character", "there", "whatever", "it", "is", "will", "get",   
         "before", "you", "here"));  
     Set<String> sorted = reverseAndSort(unsorted);  
     System.out.println("***** UNSORTED *****");  
     System.out.println(unsorted.toString());  
     System.out.println("***** SORTED *****");  
     System.out.println(sorted.toString());  
     long end = System.currentTimeMillis();  
     System.out.printf("Time taken: %d\n", (end - start));  
     System.out.printf("Unsorted size: %d\n", unsorted.size());  
     System.out.printf("Sorted size: %d\n", sorted.size());  
   }  
   public static Set<String> reverseAndSort(Set<String> unsorted) {  
     Set<String> sorted = new TreeSet<>();  
     for (String aStr : unsorted) {  
       if(aStr != null) {  
         sorted.add(reverseWithStringBuilder(aStr));  
       }    
     }  
     return normalizeSet(sorted);  
   }  
   static String reverseString(String aStr) {  
     String reversed = "";  
     for (int i = aStr.length() - 1; i >= 0; i--) {  
       reversed += aStr.charAt(i);  
     }  
     return reversed;  
   }  
   static Set<String> normalizeSet(Set<String> set) {  
     Set<String> finalSet = new LinkedHashSet<>();  
     Objects.requireNonNull(set, "passed set is null");  
     for (String aStr : set) {  
       if(aStr != null) {  
         finalSet.add(reverseWithStringBuilder(aStr));  
       }  
     }  
     return finalSet;  
   }  
   // Faster than reverseString()  
   static String reverseWithStringBuilder(String aStr) {  
     Objects.requireNonNull(aStr, "passed String cannot be null");  
     return new StringBuilder(aStr).reverse().toString();  
   }  
 }  
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