✨ Day 7; Week 1 ✔️

Author: AkashRajpurohit

README.md

@@ -11,6 +11,7 @@
 4. [Power of Four](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/549/week-1-august-1st-august-7th/3412/) ➡️ [CPP Solution](Week1/powerOfFour.cpp)
 5. [Add and Search Word - Data structure design](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/549/week-1-august-1st-august-7th/3413/) ➡️ [CPP Solution](Week1/wordDictionary.cpp)
 6. [Find All Duplicates in an Array](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/549/week-1-august-1st-august-7th/3414/) ➡️ [CPP Solution](Week1/findDuplicates.cpp)
+7. [Vertical Order Traversal of a Binary Tree](https://leetcode.com/explore/challenge/card/august-leetcoding-challenge/549/week-1-august-1st-august-7th/3415/) ➡️ [CPP Solution](Week1/verticalTraversal.cpp)
 
 ## Where to find me? 🌟
 * [Website](https://akashwho.codes/)

Week1/verticalTraversal.cpp

@@ -0,0 +1,64 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+ *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+ * };
+ */
+class Solution {
+    void dfs(TreeNode* root, int x, int y, vector<pair<int, pair<int, int>>>& list) {
+        if(root == NULL) return;
+        
+        list.push_back(make_pair(root->val, make_pair(x, y)));
+        
+        dfs(root->left, x - 1, y - 1, list);
+        dfs(root->right, x + 1, y - 1, list);
+    }
+public:
+    static bool compare(pair<int, pair<int, int>> L1, pair<int, pair<int, int>> L2) {
+        // If x is same
+        if(L1.second.first == L2.second.first) {
+            // If y is same
+            if(L1.second.second == L2.second.second) {
+                return L1.first < L2.first;
+            } else {
+                return L1.second.second > L2.second.second;
+            }
+        } else {
+            return L1.second.first < L2.second.first; 
+        }
+    }
+    
+    vector<vector<int>> verticalTraversal(TreeNode* root) {
+        vector<vector<int>> res;
+        vector<pair<int, pair<int, int>>> list;
+        map<int, vector<int>> m;
+        
+        dfs(root, 0, 0, list);
+        
+        sort(list.begin(), list.end(), compare);
+        
+        for(pair<int, pair<int, int>> l: list) {
+            vector<int> line;
+            
+            if(m.find(l.second.first) != m.end()) {
+                line = m[l.second.first];
+            } else {
+                line = {};
+            }
+            
+            line.push_back(l.first);
+            m[l.second.first] = line;
+        }
+        
+        for(auto &x: m) {
+            res.push_back(x.second);
+        }
+        
+        return res;
+    }
+};