add khushal87 new codes

.vscode/c_cpp_properties.json

@@ -11,7 +11,7 @@
  "_UNICODE"
  ],
  "windowsSdkVersion": "10.0.17763.0",
- "compilerPath": "C:/Program Files/CodeBlocks/MinGW/bin/g++.exe",
+ "compilerPath": "C:/TDM-GCC-32/bin/g++.exe",
  "cStandard": "c17",
  "cppStandard": "c++17",
  "intelliSenseMode": "windows-gcc-x64"

.vscode/settings.json

@@ -1,5 +1,8 @@
 {
  "files.associations": {
- "conio.h": "c"
+ "conio.h": "c",
+ "array": "cpp",
+ "string": "cpp",
+ "string_view": "cpp"
  }
 }

BST/kth_smallest_element_in_bst.cpp

@@ -0,0 +1,28 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+int solve(Node *root, int &k)
+{
+ if (root == nullptr)
+ return 0;
+ else
+ {
+ int left = solve(root->left, k);
+ if (left)
+ return left;
+ k -= 1;
+ if (k == 0)
+ {
+ return root->data;
+ }
+ int right = solve(root->right, k);
+ return right;
+ }
+}

BST/lca.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+Node *lca(Node *root, int n1, int n2)
+{
+ //Your code here
+ if (root == nullptr)
+ return nullptr;
+ if (root->data > n1 && root->data > n2)
+ return lca(root->left, n1, n2);
+ if (root->data < n1 && root->data < n2)
+ return lca(root->right, n1, n2);
+ return root;
+}

Tree/construct_tree_from_inorder_and_postorder.cpp

@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+Node *newNode(int data)
+{
+ Node *temp = NULL;
+ temp->data = data;
+ temp->left = temp->right = NULL;
+ return temp;
+}
+
+int search(vector<int> in, int start, int end, int x)
+{
+ for (int i = start; i <= end; i++)
+ {
+ if (in[i] == x)
+ {
+ return i;
+ }
+ }
+}
+
+Node *buildTree(vector<int> in, vector<int> pre, int start, int end)
+{
+ static int preIdx = 0;
+ if (start > end)
+ {
+ return nullptr;
+ }
+ Node *tNode = newNode(pre[preIdx++]);
+ if (start == end)
+ {
+ return tNode;
+ }
+ int idx = search(in, start, end, tNode->data);
+ tNode->left = buildTree(in, pre, start, preIdx - 1);
+ tNode->right = buildTree(in, pre, preIdx + 1, end);
+ return tNode;
+}

Tree/inorder_predecessor.cpp

@@ -0,0 +1,67 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+Node *searchData(Node *root, int data)
+{
+ if (root == nullptr)
+ return nullptr;
+ else
+ {
+ if (root->data == data)
+ return root;
+ else if (root->data > data)
+ {
+ return searchData(root->left, data);
+ }
+ else
+ {
+ return searchData(root->right, data);
+ }
+ }
+}
+
+int inorderPredecessor(Node *root, int data)
+{
+ if (root == nullptr)
+ {
+ return -1;
+ }
+ else
+ {
+ Node *p = searchData(root, data);
+ if (p->left != nullptr)
+ {
+ Node *temp = p->left;
+ while (temp->right != nullptr)
+ {
+ temp = temp->right;
+ }
+ return temp->data;
+ }
+ else
+ {
+ Node *s = root;
+ Node *ans = NULL;
+ while (p->data != s->data)
+ {
+ if (p->data > s->data)
+ {
+ ans = s;
+ s = s->right;
+ }
+ else
+ {
+ s = s->left;
+ }
+ }
+ return ans ? ans->data : 0;
+ }
+ }
+}

Tree/inorder_successor.cpp

@@ -0,0 +1,67 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+Node *searchData(Node *root, int data)
+{
+ if (root == nullptr)
+ return nullptr;
+ else
+ {
+ if (root->data == data)
+ return root;
+ else if (root->data > data)
+ {
+ return searchData(root->left, data);
+ }
+ else
+ {
+ return searchData(root->right, data);
+ }
+ }
+}
+
+int inorderPredecessor(Node *root, int data)
+{
+ if (root == nullptr)
+ {
+ return -1;
+ }
+ else
+ {
+ Node *p = searchData(root, data);
+ if (p->right != nullptr)
+ {
+ Node *temp = p->right;
+ while (temp->left != nullptr)
+ {
+ temp = temp->left;
+ }
+ return temp->data;
+ }
+ else
+ {
+ Node *s = root;
+ Node *ans = NULL;
+ while (p->data != s->data)
+ {
+ if (p->data < s->data)
+ {
+ ans = s;
+ s = s->left;
+ }
+ else
+ {
+ s = s->right;
+ }
+ }
+ return ans ? ans->data : 0;
+ }
+ }
+}

Tree/lca.cpp

@@ -0,0 +1,26 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node
+{
+ int data;
+ Node *left;
+ Node *right;
+};
+
+Node *lca(Node *root, int n1, int n2)
+{
+ //Your code here
+ if (root == nullptr)
+ return nullptr;
+ if (root->data == n1 || root->data == n2)
+ {
+ return root;
+ }
+ Node *left = lca(root->left, n1, n2);
+ Node *right = lca(root->right, n1, n2);
+ if (left != nullptr && right != nullptr)
+ return root;
+ else
+ return left ? left : right;
+}