add solution for hw4:4749

java/wordStat/WordStatLengthPrefix.java

@@ -0,0 +1,79 @@
+import java.io.*;
+import java.util.*;
+
+public class WordStatLengthPrefix {
+  public static void main(String[] args) {
+    if (args.length != 2) {
+      System.err.println("incorrect input!");
+      System.err.println("usage: java WordStat inputFile outputFile");
+    }
+
+    String inputFileName = args[0];
+    String outputFileName = args[1];
+    try {
+      BufferedReader r = new BufferedReader(new FileReader(inputFileName));
+
+      Map<String, WordInfo> wordMap = new HashMap<>();
+      StringBuilder sb = new StringBuilder();
+      int wordIndex = 0;
+
+      int data = r.read();
+      while (data != -1) {
+        char c = (char) data;
+
+        if (Character.getType(c) == Character.DASH_PUNCTUATION || 
+            Character.isLetter(c) || c == '\'') {
+          sb.append(c);
+        } else {
+          if (sb.length() > 0) {
+            String word = sb.toString().toLowerCase();
+            if (word.length() != 1) {
+              String prefix = word.substring(0, word.length() / 2);
+              if (wordMap.containsKey(prefix)) {
+                wordMap.get(prefix).count++;
+              } else {
+                wordMap.put(prefix, new WordInfo(prefix, 1, wordIndex));
+                wordIndex++;
+              }
+            }
+            sb.setLength(0);
+          }
+        }
+        
+        data = r.read();
+      }
+
+
+      if (sb.length() > 0) {
+         String word = sb.toString().toLowerCase();
+         if (word.length() != 1) {
+           String prefix = word.substring(0, word.length() / 2);
+           if (wordMap.containsKey(prefix)) {
+             wordMap.get(prefix).count++;
+           } else {
+             wordMap.put(prefix, new WordInfo(prefix, 1, wordIndex));
+             wordIndex++;
+           }
+         }
+      }
+
+      r.close();
+
+      List<WordInfo> sortedWords = new ArrayList<>(wordMap.values());
+      sortedWords.sort(Comparator.comparingInt((WordInfo w) -> w.word.length())
+                                 .thenComparingInt(w -> w.firstIndex));
+
+
+      PrintWriter writer = new PrintWriter(outputFileName, "UTF-8");
+      
+      for (WordInfo info : sortedWords) {
+        writer.println(info.word + " " + info.count);
+      }
+
+      writer.close();
+
+    } catch (Exception ex) {
+      System.err.println("An error occured: " + ex.getMessage());
+    }
+  }
+}