Merge pull request #1368 from GunjanMA/dev

Added code for vertical order traversal of a tree | C++

Author: i-vishi

Tree/Traverals/CPP/vertical order traversal.cpp

@@ -0,0 +1,130 @@
+/*---Problem Description---*/
+//problem description can be found at: https://leetcode.com/problems/vertical-order-traversal-of-a-binary-tree/
+
+/*---video tutorial of approach used---*/
+// link: https://www.youtube.com/watch?v=4w2Ri4VhgZo&list=PLjhq5EHRYAeLdh0xtn2v7wbQsVc8WAB2e&index=6&ab_channel=CodeCampaign
+
+#include<bits/stdc++.h>
+#include<sstream>
+using namespace std;
+
+/*----STRUCTURE OF TREE NODE-----*/
+
+class TreeNode{
+    public:
+    int val;
+    TreeNode* left;
+    TreeNode* right;
+
+    TreeNode (int data){
+        this->val=data;
+        this->left=NULL;
+        this->right=NULL;
+    }
+};
+
+
+// Function to Build Tree 
+
+TreeNode* Buildtree()
+{
+    int a;
+    cin >> a;
+    TreeNode *root = new TreeNode(a);
+    queue<TreeNode*> q;
+    q.push(root);
+    while (!q.empty())
+    {
+        cin >> a;
+        if (a != -1)
+        {
+            TreeNode *temp = new TreeNode(a);
+            if (q.front()->left == NULL){
+                q.front()->left = temp;
+            }
+            else
+            {
+                q.front()->right = temp;
+                q.pop();
+            }
+            q.push(temp);
+        }
+        else
+        {
+            if (q.front()->left == NULL)
+            {
+                cin >> a;
+                if (a == -1){
+                    q.pop();
+                }
+                else{
+                    TreeNode *temp1 = new TreeNode(a);
+                    q.front()->right = temp1;
+                    q.pop();
+                    q.push(temp1);
+                }
+            }
+            else{
+                q.pop();
+            }
+        }
+    }
+    return root;
+}
+
+
+/*-------- FUNCTION FOR VERTICAL ORDER TRAVERSAL---------*/
+
+void PrintVerticalOrder(TreeNode* root, int d, map<int, vector<int> > &m){
+    if(root==NULL){
+        return;
+    }
+    m[d].push_back(root->val);
+    PrintVerticalOrder(root->left,d-1,m);
+    PrintVerticalOrder(root->right,d+1,m);
+}
+
+// Driver Code
+
+int main(){
+	// fast I/O
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    
+	//Buildtree is function to build tree (as per input or your convienience, you can define it)
+    TreeNode* root=Buildtree();
+	
+
+    map<int,vector<int> > m;
+    PrintVerticalOrder(root,0,m);
+	
+	//printing the vertical order traversal
+    for(auto p:m){
+        for(auto x:p.second){
+            cout<<x<<" ";
+        }
+        cout<<endl;
+    }
+
+
+    return 0;
+}
+
+/*---- SAMPLE INPUT/OUTPUT FOR A TREE ----*/
+/*
+input : 1 2 3 4 5 6  -1 -1 -1 -1 -1 -1 -1
+tree corresponding to the input: 
+
+             1
+          /      \
+       2           3
+    /     \       /
+   4       5     6
+
+output:
+4
+2
+1 5 6
+3
+this is the vertical order traversal of a tree
+*/