diff --git a/src/Practice.java b/src/Practice.java
index ca8e22b..71634cd 100644
--- a/src/Practice.java
+++ b/src/Practice.java
@@ -1,5 +1,9 @@
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Queue;
 import java.util.Set;
 
 public class Practice {
@@ -12,7 +16,14 @@ public class Practice {
      * @return the sum of the odd numbers in the array
      */
     public static int oddSum(int[] nums) {
-        return 0;
+        if(nums == null) return 0;
+        int sum = 0;
+        for(int num: nums) {
+            if (num % 2 != 0) {
+                sum += num;
+            }
+        }
+        return sum;
     }
 
     /**
@@ -27,7 +38,24 @@ public static int oddSum(int[] nums) {
      * @throws NullPointerException if words is null
      */
     public static String shortestWord(Set<String> words) {
-        return null;
+        //"kumquat", "date", "fig", "grape", "cherry"
+        if (words == null) { throw new NullPointerException(); }
+        if (words.isEmpty()) { throw new IllegalArgumentException(); }
+        
+        int length = Integer.MAX_VALUE;
+        String shortest = "";
+        for(String word: words){
+            if (word.length() < length) {
+                shortest = word;
+                length = word.length();
+            } else if (word.length() == length) {
+                if (word.compareTo(shortest) < 0) {
+                    shortest = word;
+                }
+            }
+        }
+
+        return shortest;
     }
 
     /**
@@ -40,7 +68,14 @@ public static String shortestWord(Set<String> words) {
      * @throws NullPointerException if ages is null
      */
     public static Set<String> adults(Map<String, Integer> ages) {
-        return null;
+        if (ages == null) { throw new NullPointerException(); }
+        Set<String> adult = new HashSet<>();
+        for(String age: ages.keySet()){
+            if (ages.get(age) >= 18) {
+                adult.add(age);
+            }
+        }
+        return adult;
     }
 
     /**
@@ -51,7 +86,14 @@ public static Set<String> adults(Map<String, Integer> ages) {
      * @throws IllegalArgumentException if head is null
      */
     public static int biggestNumber(ListNode<Integer> head) {
-        return 0;
+        if (head == null) { throw new IllegalArgumentException();}
+        ListNode<Integer> current = head;
+        int max = head.data;
+        while (current != null) {
+            max = Math.max(max, current.data);
+            current = current.next;
+        }
+        return max;
     }
 
     /**
@@ -68,7 +110,18 @@ public static int biggestNumber(ListNode<Integer> head) {
      * @return a frequency map of values in the list
      */
     public static <T> Map<T, Integer> frequencies(ListNode<T> head) {
-        return null;
+        if (head == null) { return new HashMap<>();}
+        Map<T, Integer> frequency = new HashMap<>();
+        ListNode<T> current = head;
+        while (current != null) {
+            if (!frequency.containsKey(current.data)) {
+                frequency.put(current.data, 1);
+            } else {
+                frequency.put(current.data, frequency.get(current.data) + 1);
+            }
+            current = current.next;
+        }
+        return frequency;
     }
 
 
@@ -81,7 +134,10 @@ public static <T> Map<T, Integer> frequencies(ListNode<T> head) {
      * @return the number of levels in the tree
      */
     public static int levelCount(BinaryTreeNode<?> root) {
-        return 0;
+        if (root == null) { return 0; }
+        int leftTree = levelCount(root.left) + 1;
+        int leftRight = levelCount(root.right) + 1;
+        return Math.max(leftTree, leftRight);
     }
 
 
@@ -109,7 +165,26 @@ public static int levelCount(BinaryTreeNode<?> root) {
      * @return the sum of the nodes at the given level
      */
     public static int sumAtLevel(BinaryTreeNode<Integer> root, int level) {
-        return 0;
+        if (root == null) { return 0;}
+
+        Queue<BinaryTreeNode<Integer>> q = new LinkedList<>(); // 1
+        int sum = 0; // 7 + 9 + 2
+        int L = 1; // 3
+        q.add(root);
+
+        while(!q.isEmpty()){
+            for(int i = q.size(); i > 0; i--){
+                BinaryTreeNode<Integer> current = q.poll(); // 7 9 2
+                if (L == level) {
+                    sum += current.data;
+                }
+
+                if (current.left != null){ q.add(current.left);}
+                if (current.right != null){ q.add(current.right);}
+            }
+            L += 1;
+        }
+        return sum;
     }
 
 
@@ -124,7 +199,27 @@ public static int sumAtLevel(BinaryTreeNode<Integer> root, int level) {
      * @return true if the sums are equal, false otherwise
      */
     public static boolean sumMatch(BinaryTreeNode<Integer> root, ListNode<Integer> head) {
-        return false;
+        int rootSum = sumMatchHelper(root);
+        int listSum = sumMatchHelper(head);
+        return rootSum == listSum ? true : false;
+    }
+
+    public static int sumMatchHelper(BinaryTreeNode<Integer> root){
+        if (root == null) return 0;
+        int leftTree = sumMatchHelper(root.left);
+        int rightTree = sumMatchHelper(root.right);
+        return root.data + leftTree + rightTree ;
+    }
+
+    public static int sumMatchHelper(ListNode<Integer> head){
+        if(head == null) return 0;
+        ListNode<Integer> current = head;
+        int sum = 0;
+        while (current != null) {
+            sum += current.data;
+            current = current.next;
+        }
+        return sum;
     }
 
     /**
@@ -136,7 +231,12 @@ public static boolean sumMatch(BinaryTreeNode<Integer> root, ListNode<Integer> h
      * @return the sum of all the tree's values
      */
     public static int nbSum(TreeNode<Integer> root) {
-        return 0;
+        if (root == null) return 0;
+        int sum = root.data;
+        for(TreeNode<Integer> child: root.children){
+            sum += nbSum(child);
+        }
+        return sum;
     }
 
     /**
@@ -168,7 +268,15 @@ public static int nbSum(TreeNode<Integer> root) {
      * @return the count of nodes that do not have siblings, EXCLUDING THE ROOT
      */
     public static int onlyChildCount(TreeNode<?> root) {
-        return 0;
+        if(root == null) return 0;
+        int count = 0;
+
+        for(TreeNode<?> child: root.children){
+            if (root.children.size() == 1) count++;
+            count += onlyChildCount(child);
+        }
+
+        return count;
     }
 
     /**
@@ -205,7 +313,32 @@ public static int onlyChildCount(TreeNode<?> root) {
      * @param root the root value of the tree
      * @return the depth of the tree, or 0 if the tree is null or the root is not present in the tree
      */
+    /*
+    /*
+        Map:                          Tree:
+        A -> [B, E, C]                 A
+        B -> [E]                     / | \
+        E -> []                    B   E   C
+        C -> [D, Q]                |     /  \
+        D -> [Z]                   E    D    Q
+        Q -> []                          \
+        Z -> []                           Z
+    */
+   
     public static <T> int maxDepth(Map<T, List<T>> tree, T root) {
-        return 0;
+        if (root == null || tree == null || !tree.containsKey(root)) return 0;
+        int depth = maxDepthHelper(tree, root);
+        return depth;
+    }
+    
+    public static <T> int maxDepthHelper(Map<T, List<T>> tree, T root){
+        if(!tree.containsKey(root)) return 1;
+        int depth = 1;
+        List<T> children = tree.get(root);
+
+        for(T child: children) {
+            depth = Math.max(maxDepthHelper(tree, child) + 1, depth);
+        }
+        return depth;
     }
 }
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