ThirdLatestDate algorithm

Author: melmedany

src/main/java/Date.java

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+/**
+ * @author medany
+ */
+
+public class Date {
+
+	int year;
+	int month;
+	int day;
+
+	public Date(String date) {
+		String[] d = date.split("-");
+		this.day = Integer.parseInt(d[0]);
+		this.month = Integer.parseInt(d[1]);
+		this.year = Integer.parseInt(d[2]);
+	}
+
+	@Override
+	public String toString() {
+		return day + "-" + month + "-" + year;
+	}
+}

src/main/java/ThirdLatestDate.java

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+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+/**
+ * @author medany
+ */
+
+/*
+ * find the latest thied date among array of custom Date object of day, month
+ * and year integers
+ */
+
+public class ThirdLatestDate {
+
+	public Date solve(Date[] dates) {
+
+		Map<Integer, Set<Date>> sortedDates = new TreeMap<Integer, Set<Date>>(new Comparator<Integer>() {
+			@Override
+			public int compare(Integer i, Integer j) {
+				return j.compareTo(i);
+			}
+
+		});
+
+		for (Date date : dates) {
+			if (sortedDates.containsKey(date.year)) {
+				sortedDates.get(date.year).add(date);
+			} else {
+				Set<Date> yearDates = new TreeSet<Date>(new Comparator<Date>() {
+
+					SimpleDateFormat f = new SimpleDateFormat("dd-MM-yyyy");
+
+					public int compare(Date d1, Date d2) {
+
+						java.util.Date date1 = null, date2 = null;
+						try {
+							date1 = f.parse(d1.day + "-" + d1.month + "-" + d1.year);
+							date2 = f.parse(d2.day + "-" + d2.month + "-" + d2.year);
+						} catch (ParseException e) {
+						}
+						return date2.compareTo(date1);
+					}
+				});
+
+				yearDates.add(date);
+				sortedDates.put(date.year, yearDates);
+			}
+		}
+
+		Date thirdLatesDate = null;
+		int i = 0;
+		for (Set<Date> sd : sortedDates.values()) {
+			for (Date d : sd) {
+				thirdLatesDate = d;
+				if (i == 2) {
+					return d;
+				} else {
+					i++;
+					continue;
+				}
+			}
+		}
+
+		return thirdLatesDate;
+
+	}
+}

test/main/java/ThirdLatestDateTest.java

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+import java.text.ParseException;
+
+import org.junit.Assert;
+import org.junit.ComparisonFailure;
+import org.junit.Test;
+
+/**
+ * @author medany
+ */
+
+public class ThirdLatestDateTest {
+
+	private ThirdLatestDate alg = new ThirdLatestDate();
+	private Date[] dates = null;
+	Date actual = null, expected = null;
+
+	@Test
+	public void Test_1() throws ParseException {
+
+		dates = getDates(
+				new String[] { "14-04-2001", "29-12-2061", "21-10-2019", "07-01-1973", "19-07-2014", "11-03-1992" });
+
+		actual = alg.solve(dates);
+		expected = new Date("19-07-2014");
+
+		test(expected, actual);
+
+	}
+
+	@Test
+	public void Test_2() {
+
+		dates = getDates(new String[] { "14-04-2001", "29-12-2061", "21-10-2019", "07-01-1973", "19-07-2014",
+				"11-03-1992", "21-10-2019" });
+
+		actual = alg.solve(dates);
+		expected = new Date("19-07-2014");
+
+		test(expected, actual);
+	}
+
+	@Test
+	public void Test_3() {
+
+		dates = getDates(new String[] { "14-04-2001", "29-12-2061", "29-12-2061", "21-10-2019", "07-01-1973",
+				"19-07-2014", "19-07-2014", "11-03-1992" });
+
+		actual = alg.solve(dates);
+		expected = new Date("19-07-2014");
+
+		test(expected, actual);
+	}
+
+	@Test
+	public void Test_4() {
+
+		dates = getDates(new String[] { "01-10-2015", "01-09-2015", "01-08-2015", "01-07-2015", "01-06-2015" });
+
+		actual = alg.solve(dates);
+		expected = new Date("01-08-2015");
+
+		test(expected, actual);
+	}
+
+	@Test
+	public void Test_5() {
+
+		dates = getDates(
+				new String[] { "25-01-2015", "24-01-2015", "23-01-2015", "22-01-2015", "21-01-2015", "20-01-2015" });
+
+		actual = alg.solve(dates);
+		expected = new Date("23-01-2015");
+
+		test(expected, actual);
+	}
+
+	@Test
+	public void Test_6() {
+
+		dates = getDates(new String[] { "01-08-2011", "01-09-2012", "01-10-2015", "01-11-2014", "01-12-2013" });
+
+		actual = alg.solve(dates);
+		expected = new Date("01-12-2013");
+
+		test(expected, actual);
+	}
+
+	@Test
+	public void Test_7() {
+
+		dates = getDates(new String[] { "18-01-1998", "19-01-1999", "20-01-2002", "21-01-2001", "22-01-2000" });
+
+		actual = alg.solve(dates);
+		expected = new Date("22-01-2000");
+
+		test(expected, actual);
+	}
+
+	private Date[] getDates(String[] datesStrings) {
+		Date[] dates = new Date[datesStrings.length];
+		for (int i = 0; i < datesStrings.length; i++) {
+			dates[i] = new Date(datesStrings[i]);
+		}
+		return dates;
+	}
+
+	private void test(Date expected, Date actual) {
+		try {
+			Assert.assertEquals(expected.toString(), actual.toString());
+		} catch (ComparisonFailure failed) {
+			System.out.println(failed.getStackTrace()[3].getMethodName() + " failed, " + failed.getMessage());
+		}
+	}
+}