| # | 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||

packagecom.fishercoder.solutions;

importjava.util.ArrayList;

importjava.util.List;

importjava.util.TreeMap;

publicclass_2150 {

publicstaticclassSolution1 {

publicList<Integer>findLonely(int[]nums) {

TreeMap<Integer,Integer>treeMap =newTreeMap<>();

for (intnum :nums) {

treeMap.put(num,treeMap.getOrDefault(num,0) +1);

}

List<Integer>ans =newArrayList<>();

for (intkey :treeMap.keySet()) {

if (treeMap.get(key) >1) {

continue;

}else {

if (!treeMap.containsKey(key -1) && !treeMap.containsKey(key +1)) {

ans.add(key);

}

}

}

returnans;

}

}

}