k-th smallest element in bst added

Trees/kth_smallest_element_in_bst.cpp

@@ -0,0 +1,57 @@
+#include<iostream>
+#include<climits>
+#include<queue>
+#include<algorithm>
+using namespace std;
+
+class TreeNode {
+	public:
+	int val;
+	TreeNode* left;
+	TreeNode* right;
+
+	TreeNode(int val) {
+		this->val = val;
+		left = NULL;
+		right = NULL;
+	}
+
+	~TreeNode() {
+		delete left;
+		delete right;
+	}
+};
+
+int kthSmallest(TreeNode* root, int k) {
+    if(!root){return 0;}
+    vector<int>v;
+    queue<TreeNode*>q;
+    q.push(root);
+    while(!q.empty()){
+        root=q.front();
+        q.pop();
+        v.push_back(root->val);
+        if(root->left){q.push(root->left);}
+        if(root->right){q.push(root->right);}
+    }
+    sort(v.begin(), v.end());
+    if(v.size()<k){return 0;}
+    return v[k-1];
+}
+
+int main(){
+    TreeNode* root = new TreeNode(3);
+    root->left = new TreeNode(1);
+    root->right = new TreeNode(4);
+    root->left->right = new TreeNode(2);
+
+    int k = 2;
+    int result = kthSmallest(root, k);
+    cout << "The " << k << "th smallest element is: " << result << endl;
+
+
+    delete root;
+
+    return 0;
+
+}