Nitin Verma

🧩 Solved: Find Eventual Safe States on @LeetCode 💡 Idea: Safe nodes = nodes that don’t lead to cycles. Approach: • Reverse graph • Track indegrees • Start from terminal nodes • Use BFS (Topo Sort) to eliminate unsafe nodes ⏱️ Time: O(V + E) 📦 Space: O(V + E)

Solved "Is Graph Bipartite?" on @LeetCode Idea: Try coloring the graph with 2 colors - Neighbor → opposite color - Same color conflict → not bipartite - Handle disconnected graphs too! ⏱️ Time: O(V + E) 📦 Space: O(V) #LeetCode #DSA #Graphs

Solved “Number of Enclaves” on @LeetCode # Used Multi-Source BFS from boundary cells to mark all land connected to the edge, then counted the remaining unreachable land cells. ⏱ Time: O(m × n) 💾 Space: O(m × n) #DSA #LeetCode #BFS #Graphs #Java #CodingJourney

Solved “Surrounded Regions” on @LeetCode 💻 🔹 Used DFS + Boundary Traversal 🔹 Start from edge 'O's → mark safe cells 🔹 Convert remaining 'O's to 'X' ⚡ Time Complexity: O(m × n) 📦 Space Complexity: O(m × n) #DSA #LeetCode #DFS #Java #Coding

Solved “01 Matrix” on @LeetCode ✅ Used Multi-Source BFS to compute the nearest 0 distance for each cell. ⚡ Time: O(m × n) ⚡ Space: O(m × n) #DSA #LeetCode #Java #BFS #Coding

Solved “Rotten Oranges” on @LeetCode Approach: Multi-source BFS using Queue to simulate rotting level by level. ⏱ Time Complexity: O(m×n) 📦 Space Complexity: O(m×n) #DSA #LeetCode #Java #BFS #CodingJourney

Solved “Flood Fill” on @LeetCode using DFS. Traversed the matrix in 4 directions and filled all connected pixels of the same color. - Time Complexity: O(m × n) - Space Complexity: O(m × n) #DSA #LeetCode #Java #DFS #CodingJourney

Solved “Number of Provinces” on @LeetCode 🚀 🔹 Used DFS to find connected components 🔹 Converted adjacency matrix → adjacency list ⏱ Time: O(n²) 💾 Space: O(n) #DSA #Java #Graphs #DFS #LeetCode #CodingJourney

Solved “Number of Islands” on @LeetCode 🔹 Used BFS to explore connected land cells 🔹 Each BFS call = one island ⏱ Time: O(m × n) 📦 Space: O(m × n) #DSA #LeetCode #BFS #Graphs #Java #CodingJourney

Solved Graph Traversal using: 🔵 BFS (Queue – level wise) 🟢 DFS (Stack/Recursion – depth wise) - @striver_79 Both run in: Time: O(V + E) Space: O(V) #DSA #Graphs #BFS #DFS #Java #CodingJourney #LearnToCode

Solved Inorder Predecessor & Successor in BST 🌳 📌 Find: • Predecessor → largest smaller value • Successor → smallest greater value ⚡ Used BST properties for efficient traversal ⏱️ Time: O(h) 💾 Space: O(1) #DSA #BST #Java #DataStructures #CodingNinjas #journey

Solved “Construct BST from Preorder Traversal” on @LeetCode 🧩 🔹 Built the BST in a single pass using preorder index & bounds ⏱️ Time: O(n) 📦 Space: O(n) #DSA #LeetCode #BST #Java #Recursion #CodingJourney

Solved Lowest Common Ancestor of a Binary Tree on @LeetCode 🌳 🔹 Used recursive DFS 🔹 No extra space or parent pointers 🔹 Clean backtracking logic ⏱️ Time: O(n) 🧠 Space: O(h) #DSA #LeetCode #Java #BinaryTree #Recursion #CodeNewbie

Solved “Binary Tree Paths” on @LeetCode Used DFS to collect all root-to-leaf paths by building paths during traversal. ⏱ Time: O(n) 📦 Space: O(h) #DSA #LeetCode #BinaryTree #DFS #Java #CodingJourney

Solved “Symmetric Tree” on @LeetCode 🧩 ✔ Checked if a binary tree is a mirror of itself ✔ Used recursive comparison of left & right subtrees ⏱ Time: O(n) 📦 Space: O(h) #DSA #LeetCode #BinaryTree #Recursion #Java #CodingJourney

Solved Binary Tree Right Side View on @LeetCode Used a clean recursive approach: 👉 Prioritize right subtree 👉 First node at each level = visible ⏱ O(n) time | 📦 O(h) space #DSA #Java #BinaryTree #Coding #LeetCode

Solved “Vertical Order Traversal of a Binary Tree” on @LeetCode! 🌳 Used BFS + TreeMap + PriorityQueue to sort nodes by: • Column • Row • Value (when tied) Clean & elegant vertical ordering achieved! 🚀 #DSA #LeetCode #BinaryTree #Java #CodingJourney

Solved Same Tree on @LeetCode ! 🌳 Check if two binary trees are identical in structure and values. Approach Used: Recursive approach Time: O(n) Space: O(h) #DSA #Java #Recursion #BinaryTree #LeetCode #CodeNewbie

Solved “Minimum Days to Make M Bouquets” on @LeetCode Approach: ✅ Binary Search on Answers ✅ Greedy check for consecutive flowers ✅ Find smallest day to make m bouquets 🧠 Time: O(n · log(maxDay - minDay)) 💻 Space: O(1) #DSA #Java #BinarySearch #CodingNinjas #ProblemSolving

Solved “Koko Eating Bananas” 🍌 using Binary Search on Answer on @LeetCode Approach: Search for min eating speed k (1 → max pile) For each k, check if Koko can finish in h hours Adjust bounds with binary search ⏱ O(n log m) #DSA #BinarySearch #CodingNinjas #ProblemSolving