kabothu
diff --git a/‎Explore/Medium/Sorting & Searching/Sort Colors.java
Lines changed: 23 additions & 0 deletions b/‎Explore/Medium/Sorting & Searching/Sort Colors.java
Lines changed: 23 additions & 0 deletions
diff --git a/‎Explore/Medium/Sorting & Searching/Top K Frequent Elements.java
Lines changed: 29 additions & 0 deletions b/‎Explore/Medium/Sorting & Searching/Top K Frequent Elements.java
Lines changed: 29 additions & 0 deletions
diff --git a/‎Explore/Medium/Binary Tree Inorder Traversal.java renamed to ‎Explore/Medium/Trees and Graphs/Binary Tree Inorder Traversal.java b/‎Explore/Medium/Binary Tree Inorder Traversal.java renamed to ‎Explore/Medium/Trees and Graphs/Binary Tree Inorder Traversal.java
diff --git a/‎Explore/Medium/Binary Tree Zigzag Level Order Traversal.java renamed to ‎Explore/Medium/Trees and Graphs/Binary Tree Zigzag Level Order Traversal.java b/‎Explore/Medium/Binary Tree Zigzag Level Order Traversal.java renamed to ‎Explore/Medium/Trees and Graphs/Binary Tree Zigzag Level Order Traversal.java
diff --git a/‎Explore/Medium/Trees and Graphs/Populating Next Right Pointers in Each Node.java
Lines changed: 28 additions & 0 deletions b/‎Explore/Medium/Trees and Graphs/Populating Next Right Pointers in Each Node.java
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+class Solution {
+    public void sortColors(int[] nums) {
+        
+        int n0 = -1;
+        int n1 = -1;
+        int n2 = -1;
+        
+        for (int i=0;i<nums.length;i++) {
+            if (nums[i] == 0) {
+                nums[++n2] = 2;
+                nums[++n1] = 1;
+                nums[++n0] = 0;
+            }
+            else if (nums[i] == 1) {
+                nums[++n2] = 2;
+                nums[++n1] = 1;
+            }
+            else {
+                nums[++n2] = 2;
+            }
+        }
+    }
+}
@@ -0,0 +1,29 @@
+class Solution {
+    public List<Integer> topKFrequent(int[] nums, int k) {
+        List<Integer>[] bucket = new List[nums.length+1];
+        Map<Integer, Integer> frequencyMap = new HashMap<>();
+        for (int n : nums) {
+            frequencyMap.put(n, frequencyMap.getOrDefault(n, 0) + 1);
+        }
+        
+        for (int key : frequencyMap.keySet()) {
+            int frequency = frequencyMap.get(key);
+            
+            if (bucket[frequency] == null) {
+                bucket[frequency] = new ArrayList<>();
+            }
+            
+            bucket[frequency].add(key);
+        }
+        
+        List<Integer> res = new ArrayList<>();
+        
+        for (int pos = bucket.length - 1; pos >= 0 && res.size() < k; pos--) {
+            if (bucket[pos] != null) {
+                res.addAll(bucket[pos]);
+            }
+        }
+        
+        return res;
+    }
+}
@@ -0,0 +1,28 @@
+/**
+ * Definition for binary tree with next pointer.
+ * public class TreeLinkNode {
+ *     int val;
+ *     TreeLinkNode left, right, next;
+ *     TreeLinkNode(int x) { val = x; }
+ * }
+ */
+public class Solution {
+    public void connect(TreeLinkNode root) {
+        
+        TreeLinkNode start=root;
+        
+        while(start!=null){
+            
+            TreeLinkNode cur=start;
+            
+            while(cur!=null){
+                if(cur.left!=null) cur.left.next=cur.right;
+                if(cur.right!=null && cur.next!=null) cur.right.next=cur.next.left;
+
+                cur=cur.next;
+            }
+            
+            start=start.left;
+        }
+    }
+}