Comapre List - SO Solution

Author: Arpit Aggarwal

src/com/test/so/solutions/CountInt.java

@@ -0,0 +1,14 @@
+package com.test.so.solutions;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class CountInt {
+
+	public static void main(String[] args) {
+		List<String> list = Arrays.asList("a", "b", "c", "d");
+		int count = (int) IntStream.range(0, list.size()).count();
+		System.out.println(count);
+	}
+}

src/com/test/so/solutions/CountSimilar.java

@@ -0,0 +1,95 @@
+package com.test.so.solutions;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
+
+final class SearchList {
+	private final String area;
+	private final String location;
+
+	public SearchList(String area, String location) {
+		this.area = area;
+		this.location = location;
+	}
+
+	public String getArea() {
+		return area;
+	}
+
+	@Override
+	public String toString() {
+		return "SearchList [area=" + area + ", location=" + location + "]";
+	}
+
+	public String getLocation() {
+		return location;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((area == null) ? 0 : area.hashCode());
+		result = prime * result
+				+ ((location == null) ? 0 : location.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		SearchList other = (SearchList) obj;
+		if (area == null) {
+			if (other.area != null)
+				return false;
+		} else if (!area.equals(other.area))
+			return false;
+		if (location == null) {
+			if (other.location != null)
+				return false;
+		} else if (!location.equals(other.location))
+			return false;
+		return true;
+	}
+
+}
+
+public class CountSimilar {
+	public static void main(String[] args) {
+
+		List<SearchList> searchListList = new ArrayList<>();
+		searchListList.add(new SearchList("A", "India"));
+		searchListList.add(new SearchList("B", "India"));
+		searchListList.add(new SearchList("A", "India"));
+		searchListList.add(new SearchList("A", "USA"));
+		searchListList.add(new SearchList("A", "USA"));
+
+		int countSimilar = (int) searchListList.stream().distinct().count();
+
+		System.out.println(countSimilar);
+
+		int countSimilarByArea = searchListList
+				.stream()
+				.collect(
+						Collectors.toCollection(() -> new TreeSet<SearchList>((
+								p1, p2) -> p1.getArea().compareTo(p2.getArea()))))
+				.size();
+		System.out.println(countSimilarByArea);
+
+		int countSimilarByLocation = searchListList
+				.stream()
+				.collect(
+						Collectors.toCollection(() -> new TreeSet<SearchList>((
+								p1, p2) -> p1.getLocation().compareTo(
+								p2.getLocation())))).size();
+
+		System.out.println(countSimilarByLocation);
+	}
+}

src/com/test/so/solutions/ListCompare.java

@@ -0,0 +1,26 @@
+package com.test.so.solutions;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class ListCompare {
+	public static void main(String[] args) {
+
+		List<String> list1 = new ArrayList<String>();
+		list1.add("A");
+		list1.add("B");
+		list1.add("C");
+
+		List<String> list2 = new ArrayList<String>();
+		list2.add("A");
+		list2.add("B");
+		list2.add("D");
+
+		IntStream.range(0, list1.size()).forEach(i -> {
+			if (list1.get(i).equals(list2.get(i)))
+				System.out.println(i);
+		});
+	}
+
+}

src/com/test/so/solutions/ListSort.java

@@ -20,7 +20,8 @@ public static void main(String[] args) {
 		list.add(new ListSort(3, "adf"));
 		list.add(new ListSort(6, "aad"));
 		list.add(new ListSort(2, "xx"));
-		list.sort((s1, s2) -> s1.a - s2.a);
+		
+	    list.sort((s1, s2) -> s1.a - s2.a);
 
 		for (ListSort element : list) {
 			System.out.println(element.a + element.b);

src/com/test/so/solutions/ListToString.java

@@ -12,9 +12,7 @@ public static void main(String[] args) {
 		list.add("three");
 
 		System.out.println(String.join(",", list));
-		
 		System.out.println(list.stream().collect(Collectors.joining(",")));
-		
 		System.out.println(getStringPriorJava8(list));
 	}
 

src/com/test/so/solutions/OddNumbers.java

@@ -9,7 +9,7 @@ public class OddNumbers {
 	public static void main(String[] args) {
 		System.out.print("Enter Number : ");
 		int n = scanner.nextInt();
-		IntStream.range(0, n).filter(element -> element % 2 != 0).boxed()
+		IntStream.range(0, n).filter(element -> element % 2 != 0)
 				.forEach(System.out::println);
 	}
 }

src/com/test/streams/Reduce.java

@@ -0,0 +1,30 @@
+package com.test.streams;
+
+import java.util.stream.Stream;
+
+class Employee {
+	private final int age;
+
+	public Employee(final int age) {
+		this.age = age;
+	}
+
+	public int getAge() {
+		return age;
+	}
+}
+
+public class Reduce {
+
+	public static void main(String[] args) {
+		Employee employee = new Employee(10);
+		Employee employee1 = new Employee(15);
+		Employee employee2 = new Employee(20);
+		int sum = Stream.of(employee, employee1, employee2)
+				.map(Employee::getAge).
+				reduce(0, (a, b) -> -a + b);
+		System.out.println(sum);
+
+	}
+
+}