Merge pull request #639 from Jayesh3734/main

Added code for Burning tree

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;
+}
+
+