new soln

Author: shreymehul

78.Subsets.cs

@@ -28,4 +28,22 @@ public IList<IList<int>> Subsets(int[] nums) {
         }
         return result;
     }
+}
+
+public class Solution {
+    public IList<IList<int>> Subsets(int[] nums) {
+        IList<IList<int>> result = new List<IList<int>>();
+        Subsets(nums, 0, result, new List<int>());
+        return result;
+    }
+    private void Subsets(int[] nums, int itr, IList<IList<int>> result, IList<int> set){
+        if(itr == nums.Length){
+            result.Add(new List<int>(set));
+            return;
+        }
+        Subsets(nums, itr+1, result, set);
+        set.Add(nums[itr]);
+        Subsets(nums, itr+1, result, set);
+        set.RemoveAt(set.Count -1);
+    }
 }

979.DistributeCoins.cs

@@ -0,0 +1,50 @@
+// 979. Distribute Coins in Binary Tree
+// You are given the root of a binary tree with n nodes where each node in the tree has node.val coins. There are n coins in total throughout the whole tree.
+// In one move, we may choose two adjacent nodes and move one coin from one node to another. A move may be from parent to child, or from child to parent.
+// Return the minimum number of moves required to make every node have exactly one coin.
+
+// Example 1:
+// Input: root = [3,0,0]
+// Output: 2
+// Explanation: From the root of the tree, we move one coin to its left child, and one coin to its right child.
+// Example 2:
+// Input: root = [0,3,0]
+// Output: 3
+// Explanation: From the left child of the root, we move two coins to the root [taking two moves]. Then, we move one coin from the root of the tree to the right child.
+
+// Constraints:
+
+// The number of nodes in the tree is n.
+// 1 <= n <= 100
+// 0 <= Node.val <= n
+// The sum of all Node.val is n.
+
+/**
+ * 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 int DistributeCoins(TreeNode root) {
+        return DistributeCoins(root, null);
+    }
+
+    public int DistributeCoins(TreeNode root, TreeNode parent) {
+        if(root == null)
+            return 0;
+        int moves = DistributeCoins(root.left, root) + DistributeCoins(root.right, root);
+        int x = root.val -1;
+        if(parent != null)
+            parent.val += x;
+        moves += Math.Abs(x);
+        return moves;
+    }
+}