working solution

problem1.py

@@ -0,0 +1,24 @@
+# problem 1
+
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution:
+    def levelOrder(self, root: Optional[TreeNode]) -> List[List[int]]:
+        self.result = []
+        self.helper(root,0)
+        return self.result
+
+    def helper(self,root,depth):
+        if not root:
+            return 
+
+        if len(self.result) == depth:
+            self.result.append([])
+
+        self.helper(root.left,depth+1)
+        self.result[depth].append(root.val)
+        self.helper(root.right,depth+1)

problem2.py

@@ -0,0 +1,38 @@
+# problem 2 
+
+class Solution:
+    def canFinish(self, numCourses: int, prerequisites: List[List[int]]) -> bool:
+        course_count = [0]*numCourses
+        my_graph = {}
+
+        for prerequisite in prerequisites:
+            course_count[prerequisite[0]] +=1
+            if prerequisite[1] not in my_graph:
+                my_graph[prerequisite[1]]= []
+            my_graph[prerequisite[1]].append(prerequisite[0])
+
+        check_queue = deque()
+        count = 0
+        for i in range(numCourses):
+            if course_count[i] == 0:
+                check_queue.append(i)
+                count+=1
+
+
+        if not check_queue:
+            return False 
+        if count == numCourses:
+            return True 
+
+        while(check_queue):
+            curr_class = check_queue.popleft()
+            graph_vals = my_graph.get(curr_class)
+            if graph_vals:
+                for graph_val in graph_vals:
+                    course_count[graph_val] -=1
+                    if course_count[graph_val] == 0:
+                        count+=1
+                        check_queue.append(graph_val)
+                        if count == numCourses:
+                            return True
+        return False