Merge pull request #619 from KBhushan07/main

Leetcode Binary Tree Solutions

Author: gantavyamalviya

Trees/Leetcode-116. Populating Next Right Pointers in Each Node.cpp

@@ -0,0 +1,21 @@
+class Solution {
+public:
+ 
+ Node* connect(Node* root) {
+ if(root==NULL)
+ return NULL;
+ 
+ if(root->left){
+ root->left->next=root->right;
+ 
+ if(root->next){
+ root->right->next=root->next->left;
+ }
+ 
+ connect(root->left);
+ connect(root->right);
+ }
+ return root;
+ 
+ }
+};

Trees/Leetcode-222. Count Complete Tree Nodes.cpp

@@ -0,0 +1,19 @@
+class Solution {
+public:
+ vector<int>num;
+ int countNodes(TreeNode* root) {
+ if(root==NULL)return 0;
+ queue<TreeNode*>q;
+ q.push(root);
+ while(!q.empty()){
+ TreeNode*curr = q.front();
+ num.push_back(curr->val);
+ if(curr->left!=NULL)
+ q.push(curr->left);
+ if(curr->right!=NULL)
+ q.push(curr->right);
+ q.pop();
+ }
+ return num.size();
+ }
+};

Trees/Leetcode-226. Invert Binary Tree.cpp

@@ -0,0 +1,8 @@
+TreeNode* invertTree(TreeNode* root) {
+ if (root) {
+ invertTree(root->left);
+ invertTree(root->right);
+ swap(root->left, root->right);
+ }
+ return root;
+}

Trees/Leetcode-230. Kth Smallest Element in a BST.cpp

@@ -0,0 +1,19 @@
+class Solution {
+public:
+ vector<int>num;
+ int kthSmallest(TreeNode* root, int k) {
+ queue<TreeNode*>q;
+ q.push(root);
+ while(!q.empty()){
+ TreeNode*curr = q.front();
+ num.push_back(curr->val);
+ if(curr->left!=NULL)
+ q.push(curr->left);
+ if(curr->right!=NULL)
+ q.push(curr->right);
+ q.pop();
+ }
+ sort(num.begin(), num.end());
+ return num[k-1];
+ }
+};

Trees/Leetcode-623. Add One Row to Tree.cpp

@@ -0,0 +1,82 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ * int val;
+ * TreeNode *left;
+ * TreeNode *right;
+ * TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ * TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ * TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+public:
+ 
+ // getting all parent nodes for which we want to append nodes 
+ void getBfs(TreeNode* root, int depth , vector<TreeNode*>&v){
+ if(depth==1 && root!=NULL){
+ v.push_back(root);
+ return;
+ }
+ if(root==NULL)return;
+ 
+ getBfs(root->left , depth-1 , v);
+ getBfs(root->right , depth-1 , v);
+ 
+ return;
+ }
+ 
+ //creating nodes
+ TreeNode* createNode(int val){
+ TreeNode *temp=new TreeNode;
+ temp->val = val;
+ return temp;
+ }
+ 
+ 
+ TreeNode* addOneRow(TreeNode* root, int val, int depth) {
+ 
+ //if depth ==1
+ if(depth==1){
+ TreeNode* temp = createNode(val);
+ temp ->left = root;
+ return temp;
+ }
+ 
+ 
+ vector<TreeNode*>v;
+ getBfs(root , depth-1 , v);
+ int s = v.size();
+ 
+ for(int i=0; i<s; i++){
+ TreeNode* temp1 = createNode(val);
+ TreeNode* temp2 = createNode(val);
+ TreeNode *t = v[i];
+ if(t->left && t->right){
+ temp1->left=t->left;
+ temp2->right=t->right;
+ t->left = temp1;
+ t->right = temp2;
+ }
+ else if(t->left && t->right==NULL){
+ temp1->left=t->left;
+ t->left = temp1;
+ t->right = temp2;
+ }
+ else if(t->left==NULL && t->right){
+ temp2->right=t->right;
+ t->left = temp1;
+ t->right = temp2;
+ }
+ else{
+ t->left = temp1;
+ t->right = temp2;
+ }
+ }
+ 
+ 
+ return root;
+ 
+ 
+ }
+};