Updated solution to day 12 of June Leetcode Challenge

Author: shrinathjoshi

June Challenge/com/leetcode/JuneChallenge/week2/InsertDeleteGetRandom.java

@@ -0,0 +1,79 @@
+package com.leetcode.JuneChallenge.week2;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Random;
+
+class RandomizedSet {
+	private List<Integer> list;
+	private HashMap<Integer, Integer> map;
+	private Random rand;
+
+	/** Initialize your data structure here. */
+	public RandomizedSet() {
+		list = new ArrayList<Integer>();
+		map = new HashMap<Integer, Integer>();
+		rand = new Random();
+	}
+
+	/**
+	 * Inserts a value to the set. Returns true if the set did not already contain
+	 * the specified element.
+	 */
+	public boolean insert(int val) {
+		if (map.containsKey(val))
+			return false;
+
+		list.add(val);
+		map.put(val, list.size() - 1);
+		return true;
+
+	}
+
+	/**
+	 * Removes a value from the set. Returns true if the set contained the specified
+	 * element.
+	 */
+	public boolean remove(int val) {
+		if (!map.containsKey(val))
+			return false;
+
+		int index = map.get(val);
+		int valueAtLastIndex = list.get(list.size() - 1);
+
+		list.set(index, valueAtLastIndex);
+		map.put(valueAtLastIndex, index);
+		list.remove(list.size() - 1);
+		map.remove(val);
+		return true;
+	}
+
+	/** Get a random element from the set. */
+	public int getRandom() {
+
+		return list.get(rand.nextInt(list.size()));
+	}
+}
+
+/**
+ * Your RandomizedSet object will be instantiated and called as such:
+ * 
+ */
+
+public class InsertDeleteGetRandom {
+
+	public static void main(String[] args) {
+		RandomizedSet obj = new RandomizedSet();
+
+		System.out.println(obj.insert(1));
+		System.out.println(obj.remove(2));
+		System.out.println(obj.insert(2));
+		System.out.println(obj.getRandom());
+		System.out.println(obj.remove(1));
+		System.out.println(obj.insert(2));
+		System.out.println(obj.getRandom());
+
+	}
+
+}