Merge pull request codemistic#639 from Jayesh3734/main

Added code for Burning tree

Author: gantavyamalviya

Trees/burningTree.cpp

@@ -0,0 +1,175 @@
+// Burning tree
+
+
+#include <bits/stdc++.h>
+using namespace std;
+
+struct Node {
+ int data;
+ Node *left;
+ Node *right;
+
+ Node (int val) {
+ data = val;
+ left = right = NULL;
+ }
+};
+
+
+Node *buildTree (string str) {
+ // Corner Case
+ if (str.length() == 0 || str[0] == 'N')
+ return NULL;
+ 
+ // Creating vector of strings from input
+ // string after spliting by space
+ vector<string> ip;
+
+ istringstream iss(str);
+ for (string str; iss >> str;)
+ ip.push_back(str);
+
+ // Create the root of the tree
+ Node *root = new Node (stoi (ip[0]));
+
+ // Push the root to the queue
+ queue<Node *> queue;
+ queue.push(root);
+
+ // Starting from the second element
+ int i = 1;
+ while (!queue.empty() && i < ip.size()) {
+
+ // Get and remove the front of the queue
+ Node *currNode = queue.front();
+ queue.pop();
+
+ // Get the current Node's value from the string
+ string currVal = ip[i];
+
+ // If the left child is not null
+ if (currVal != "N") {
+
+ // Create the left child for the current Node
+ currNode->left = new Node (stoi(currVal));
+
+ // Push it to the queue
+ queue.push(currNode->left);
+ }
+
+ // For the right child
+ i++;
+ if (i >= ip.size())
+ break;
+ currVal = ip[i];
+
+ // If the right child is not null
+ if (currVal != "N") {
+
+ // Create the right child for the current Node
+ currNode->right = new Node (stoi(currVal));
+
+ // Push it to the queue
+ queue.push(currNode->right);
+ }
+ i++;
+ }
+
+ return root;
+}
+
+
+
+
+
+class Solution {
+ public:
+ Node* createParentMapping(Node* root, int target, map<Node*, Node*> &nodeToParent){
+ Node* res = NULL;
+ 
+ queue<Node*> q;
+ q.push(root);
+ nodeToParent[root] = NULL;
+ 
+ while(!q.empty()){
+ Node* front = q.front();
+ q.pop();
+ if(front->data == target){
+ res = front;
+ }
+ if(front->left){
+ nodeToParent[front->left] = front;
+ q.push(front->left);
+ }
+ if(front->right){
+ nodeToParent[front->right] = front;
+ q.push(front->right);
+ }
+ }
+ return res;
+ }
+ 
+ int burnTree(Node* targetNode, map<Node*, Node*> nodeToParent){
+ map<Node*, bool> visited;
+ queue<Node*> q;
+ q.push(targetNode);
+ visited[targetNode] = true;
+ 
+ int ans = 0;
+ 
+ while(!q.empty()){
+ bool flag = 0;
+ int size = q.size();
+ for(int i=0; i<size; i++){
+ Node* front = q.front();
+ q.pop();
+ 
+ if(front->left && !visited[front->left]){
+ flag = 1;
+ q.push(front->left);
+ visited[front->left] = 1;
+ }
+ if(front->right && !visited[front->right]){
+ flag = 1;
+ q.push(front->right);
+ visited[front->right] = 1;
+ }
+ if(nodeToParent[front] && !visited[nodeToParent[front]]){
+ flag = 1;
+ q.push(nodeToParent[front]);
+ visited[nodeToParent[front]] = 1;
+ }
+ }
+ if(flag){
+ ans++;
+ }
+ }
+ return ans;
+ }
+ 
+ int minTime(Node* root, int target){
+ map<Node*, Node*> nodeToParent;
+ Node* targetNode = createParentMapping(root, target, nodeToParent);
+ 
+ int ans = burnTree(targetNode, nodeToParent);
+ return ans;
+ }
+};
+
+int main() {
+ int t;
+ cin;
+ while (t--) {
+ string s;
+ getline(cin, s);
+ Node *root = buildTree(s);
+
+ int target;
+ cin >> target;
+ Solution ob;
+ cout << ob.minTime(root, target) << endl;
+ }
+ return 0;
+}
+
+