Create findTarget.cpp

Author: SteffiKeranJ

BST/findTarget.cpp

@@ -0,0 +1,37 @@
+/**
+ * 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 {
+private:
+    vector<int> bstArray;
+public:
+    void helper(TreeNode* root) {
+        if(!root) return;
+        helper(root->left);
+        bstArray.push_back(root->val);
+        helper(root->right);
+    }
+    
+    bool findTarget(TreeNode* root, int k) {
+        helper(root);
+        int left = 0;
+        int right = bstArray.size()-1;
+        while(left < right) {
+            int sum = bstArray[left] + bstArray[right];
+            if(sum == k) return true;
+            if(sum < k) left++;
+            else right--;
+        }
+        
+        return false;
+        
+    }
+};