add 2150

Author: fishercoder1534

README.md

@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ ★
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                  
 |-----|----------------|---------------|--------|-------------|-------------
+|2150|[Find All Lonely Numbers in the Array](https://leetcode.com/problems/find-all-lonely-numbers-in-the-array/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2150.java) ||Medium||
 |2149|[Rearrange Array Elements by Sign](https://leetcode.com/problems/rearrange-array-elements-by-sign/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2149.java) ||Medium||
 |2148|[Count Elements With Strictly Smaller and Greater Elements](https://leetcode.com/problems/count-elements-with-strictly-smaller-and-greater-elements/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2148.java) ||Easy||
 |2144|[Minimum Cost of Buying Candies With Discount](https://leetcode.com/problems/minimum-cost-of-buying-candies-with-discount/)|[Java](../master/src/main/java/com/fishercoder/solutions/_2144.java) ||Easy||

src/main/java/com/fishercoder/solutions/_2150.java

@@ -0,0 +1,27 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.TreeMap;
+
+public class _2150 {
+    public static class Solution1 {
+        public List<Integer> findLonely(int[] nums) {
+            TreeMap<Integer, Integer> treeMap = new TreeMap<>();
+            for (int num : nums) {
+                treeMap.put(num, treeMap.getOrDefault(num, 0) + 1);
+            }
+            List<Integer> ans = new ArrayList<>();
+            for (int key : treeMap.keySet()) {
+                if (treeMap.get(key) > 1) {
+                    continue;
+                } else {
+                    if (!treeMap.containsKey(key - 1) && !treeMap.containsKey(key + 1)) {
+                        ans.add(key);
+                    }
+                }
+            }
+            return ans;
+        }
+    }
+}