Construct Binary Tree solution

Author: PDKhan

construct-binary-tree-from-preorder-and-inorder-traversal/PDKhan.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    TreeNode* build(vector<int>& preorder, int& pos, vector<int>& inorder, int start, int end) {
+        if(start >= end)
+            return nullptr;
+
+        int i;
+
+        for(i = start; i < end; i++){
+            if(preorder[pos] == inorder[i])
+                break;
+        }
+
+        TreeNode* root = new TreeNode(preorder[pos]);
+
+        pos++;
+
+        root->left = build(preorder, pos, inorder, start, i);
+        root->right = build(preorder, pos, inorder, i + 1, end);
+
+        return root;
+    }
+
+    TreeNode* buildTree(vector<int>& preorder, vector<int>& inorder) {
+        int pos = 0;
+
+        return build(preorder, pos, inorder, 0, inorder.size());
+    }
+};