Create 2196. Create Binary Tree From Descriptions (#530)

Author: Chayandas07

2196. Create Binary Tree From Descriptions

@@ -0,0 +1,45 @@
+class Solution {
+public:
+    TreeNode* createBinaryTree(vector<vector<int>>& descriptions) {
+
+        unordered_map<int, TreeNode*> mp;
+        unordered_set<int> st;
+
+        for(auto desc: descriptions){
+
+            int p = desc[0];
+            int c = desc[1];
+            int left = desc[2];
+
+            if(mp.find(p) == mp.end()){
+                mp[p] = new TreeNode(p);
+            }
+
+            if(mp.find(c) == mp.end()){
+                mp[c] = new TreeNode(c);
+            }
+
+            if(left == 1){
+                mp[p]->left = mp[c];
+            }else{
+                mp[p]->right = mp[c];
+            }
+
+            st.insert(c);
+            
+        }
+
+        for(auto desc: descriptions){
+
+            int p = desc[0];
+
+            if(st.find(p) == st.end()){
+                return mp[p];
+            }
+            
+        }
+
+        return nullptr;
+        
+    }
+};