Done BFS-1

problem1.cs

@@ -0,0 +1,45 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     public int val;
+ *     public TreeNode left;
+ *     public TreeNode right;
+ *     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+public class Solution {
+    public IList<IList<int>> LevelOrder(TreeNode root) {
+        if(root == null) return [];
+        Queue<TreeNode> levelQueue = new Queue<TreeNode>();
+        levelQueue.Enqueue(root);
+        List<IList<int>> result = new List<IList<int>>();
+        while(levelQueue.Count>0)
+        {
+            List<int> temp = new List<int>();
+            int size = levelQueue.Count;
+            int count=0;
+            while(count<size)
+            {
+                TreeNode node = levelQueue.Dequeue();
+                count++;
+                temp.Add(node.val);
+                if(node.left!=null)
+                {
+                levelQueue.Enqueue(node.left);
+                }
+                if(node.right!=null)
+                {
+                levelQueue.Enqueue(node.right);
+                }
+            }
+            result.Add(temp);      
+
+        }
+        return result;
+
+    }
+}

problem2.cs

@@ -0,0 +1,40 @@
+public class Solution {
+    public bool CanFinish(int numCourses, int[][] prerequisites) {
+        int[] inDegrees = new int[numCourses];
+        Dictionary<int, List<int>> adjList = new Dictionary<int, List<int>>();
+
+        foreach (var p in prerequisites)
+        {
+            inDegrees[p[0]]++;
+            if (!adjList.ContainsKey(p[1]))
+                adjList[p[1]] = new List<int>();
+            adjList[p[1]].Add(p[0]);
+        }
+
+        Queue<int> q = new Queue<int>();
+        for (int i = 0; i < numCourses; i++)
+        {
+            if (inDegrees[i] == 0)
+                q.Enqueue(i);
+        }
+
+        int count = 0;
+        while (q.Count > 0)
+        {
+            int course = q.Dequeue();
+            count++;
+
+            if (adjList.ContainsKey(course))
+            {
+                foreach (var next in adjList[course])
+                {
+                    inDegrees[next]--;
+                    if (inDegrees[next] == 0)
+                        q.Enqueue(next);
+                }
+            }
+        }
+
+        return count == numCourses;
+    }
+}