Added bottom viewq

Author: avidLearnerInProgress

amazon/bottom_view_binary_tree.cpp

@@ -0,0 +1,104 @@
+{
+// C++ Program to print Bottom View of Binary Tree
+#include<bits/stdc++.h>
+using namespace std;
+// Tree node class
+struct Node
+{
+    int data; //data of the node
+    Node *left, *right; //left and right references
+    // Constructor of tree node
+    Node(int key)
+    {
+        data = key;
+        left = right = NULL;
+    }
+};
+// Method that prints the bottom view.
+void bottomView(Node *root);
+/* Driver program to test size function*/
+int main()
+{
+  int t;
+  struct Node *child;
+  scanf("%d
+", &t);
+  while (t--)
+  {
+     map<int, Node*> m;
+     int n;
+     scanf("%d
+",&n);
+     struct Node *root = NULL;
+     while (n--)
+     {
+        Node *parent;
+        char lr;
+        int n1, n2;
+        scanf("%d %d %c", &n1, &n2, &lr);
+        if (m.find(n1) == m.end())
+        {
+           parent = new Node(n1);
+           m[n1] = parent;
+           if (root == NULL)
+             root = parent;
+        }
+        else
+           parent = m[n1];
+        child = new Node(n2);
+        if (lr == 'L')
+          parent->left = child;
+        else
+          parent->right = child;
+        m[n2]  = child;
+     }
+     bottomView(root);
+     cout << endl;
+  }
+  return 0;
+}
+
+}
+/*This is a function problem.You only need to complete the function given below*/
+/* Tree node class
+struct Node
+{
+    int data; //data of the node
+    Node *left, *right; //left and right references
+    // Constructor of tree node
+    Node(int key)
+    {
+        data = key;
+        left = right = NULL;
+    }
+}; */
+// Method that prints the bottom view.
+void bottomView(Node *root)
+{
+   // Your Code Here
+   
+    if(root){
+        map<int, int> mp;
+        queue<pair<Node*, int>> q;
+        int hd = 0;        
+        q.push({root, hd});
+        
+        while(!q.empty()){
+            pair<Node*, int> cp = q.front();
+            Node *currNode = cp.first;
+            hd = cp.second;
+            q.pop();
+            
+            mp[hd] = currNode->data;
+            if(currNode->left != NULL)
+                q.push({currNode->left, hd - 1});
+            if(currNode->right != NULL)
+                q.push({currNode->right, hd + 1});
+        }
+        for(auto it = mp.begin(); it != mp.end(); it++){
+                cout<<it->second<<" ";
+        }
+    }
+    else
+        return;
+}