Third quicksort

src/phonebook/Contact.java

@@ -0,0 +1,20 @@
+package phonebook;
+
+public class Contact {
+
+  private String number;
+  private String name;
+
+  public Contact(String number, String name) {
+    this.number = number;
+    this.name = name;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public String getNumber() {
+    return number;
+  }
+}

src/phonebook/Main.java

@@ -1,7 +1,87 @@
 package phonebook;
 
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
 public class Main {
-    public static void main(String[] args) {
-        System.out.print("Hello world!");
+
+  private static final String CONTACT_DATA_DIRECTORY = "data/directory.txt";
+  private static final String FIND_REQUESTS_DIRECTORY = "data/find.txt";
+
+  public static void main(String[] args) throws IOException {
+    List<Contact> contacts = parseContacts();
+    quickSort(contacts);
+
+    List<String> requests = Files.readAllLines(Paths.get(FIND_REQUESTS_DIRECTORY));
+
+    long start = System.currentTimeMillis();
+    int cnt = 1;
+    for (String request : requests) {
+      Contact contact = search(contacts, request);
+      if ((Objects.nonNull(contact))) {
+        System.out.printf("%d. %s has number %s\n", cnt++, request, contact.getNumber());
+      }
+    }
+    System.out.printf("To find all entries it taken %d ms\n", System.currentTimeMillis() - start);
+  }
+
+  private static Contact search(List<Contact> contacts, String name) {
+    int lo = 0, hi = contacts.size() - 1;
+    while (lo <= hi) {
+      int mid = lo + (hi - lo) / 2;
+      Contact contact = contacts.get(mid);
+      int comparing = Objects.compare(contact.getName(), name, Comparator.naturalOrder());
+      if (comparing == 0) {
+        return contact;
+      } else if (comparing < 0) {
+        lo = mid + 1;
+      } else {
+        hi = mid - 1;
+      }
     }
+    return null;
+  }
+
+  private static void quickSort(List<Contact> contacts) {
+    quickSort(contacts, 0, contacts.size() - 1);
+  }
+
+  private static void quickSort(List<Contact> contacts, int lo, int hi) {
+    if (lo >= hi) {
+      return;
+    }
+    int p = pivot(contacts, lo, hi);
+    quickSort(contacts, lo, p - 1);
+    quickSort(contacts, p + 1, hi);
+  }
+
+  private static int pivot(List<Contact> contacts, int lo, int hi) {
+    Contact pivot = contacts.get(lo);
+    int j = lo + 1;
+    for (int i = lo + 1; i <= hi; i++) {
+      int comparing = Objects
+          .compare(pivot, contacts.get(i), Comparator.comparing(Contact::getName));
+      if (comparing >= 0) {
+        Collections.swap(contacts, i, j);
+        j++;
+      }
+    }
+    Collections.swap(contacts, lo, j - 1);
+    return j - 1;
+  }
+
+  private static List<Contact> parseContacts() throws IOException {
+    Stream<String> directoryLines = Files.lines(Paths.get(CONTACT_DATA_DIRECTORY));
+    return directoryLines.map(line -> new Contact(line.substring(0, line.indexOf(" ")),
+        line.substring(line.indexOf(" ") + 1)))
+        .collect(Collectors.toCollection(ArrayList::new));
+  }
 }