Solved Subsequence of Size 3 in Single Pass

Day 109 Backtracking patterns are repeating again — and that’s a good sign. #Day109 🧩 78. Subsets How today went: • Used recursion to explore all elements • At each step, decide to include or skip the current element • Append current subset → explore → then pop to backtrack • Move to the next index and repeat What I’m noticing: Subsets is one of the cleanest backtracking patterns: → choose → explore → undo Another revision day, but clarity is improving. Consistency continues. #LeetCode #DSA #Python #Backtracking #Recursion #LearningInPublic #Consistency

Subsets: Backtracking with Include/Exclude Decision Tree Generate all 2^n subsets via recursive binary choices — include current element or skip. Base case: processed all elements, save current subset. Backtracking pattern: modify state, recurse, undo modification. Backtracking Pattern: Modify shared state, explore branch, restore state before exploring alternate branch. This template applies to permutations, combinations, constraint satisfaction problems. Time: O(2^n) | Space: O(n) recursion depth #Backtracking #Subsets #DecisionTree #StateRestoration #Recursion #Python #AlgorithmDesign #SoftwareEngineering

Day 32/100 – Diameter of Binary Tree Today’s problem looked simple on the surface, but it really tested my understanding of tree traversal and recursion. Key Insight: The diameter of a binary tree isn’t about paths from root—it’s about the longest path between any two nodes. The trick? At every node, calculate: Left subtree height Right subtree height Update diameter = left + right This turns a potentially complex problem into a smooth DFS + height calculation. What I learned: How to combine recursion with global state Thinking beyond root-based solutions Every node can be the "center" of the longest path Time Complexity: O(n) Space Complexity: O(h) Consistency > intensity. On to Day 33 #100DaysOfCode #DataStructures #Algorithms #LeetCode #Python #CodingJourney

Subsets: Classic Backtracking Template Generate all 2^n subsets via binary decision tree — include or exclude each element. Base case: index exceeds array length, save current subset copy. Backtracking: add element, recurse, remove element (backtrack), recurse again. Critical Detail: subset.copy() is essential — without it, all results reference same list, causing incorrect final output. Each subset snapshot must be independent. Time: O(2^n) | Space: O(n) recursion #Backtracking #Subsets #DecisionTree #DeepCopy #Recursion #Python #AlgorithmDesign #SoftwareEngineering

🚀 Day 48 – LeetCode Journey Today’s challenge: Substring with Concatenation of All Words ✔️ Solved using sliding window + hashmap ✔️ Processed string in fixed-length chunks ✔️ Tracked word frequency efficiently 💡 Key Insight: Instead of checking every substring blindly, splitting the string into word-sized pieces and using a hashmap helps validate matches efficiently. Sliding window keeps the solution optimized. This problem was a great exercise in string manipulation, hashing, and window techniques 🧠 Consistency is the real game changer 🚀 #LeetCode #Day48 #SlidingWindow #HashMap #Strings #Python #ProblemSolving #CodingJourney #100DaysOfCode https://lnkd.in/gxf4RBT6

🚀 Day 43 – LeetCode Journey Today’s problem: Minimum Depth of Binary Tree ✔️ Solved using recursion (DFS) ✔️ Carefully handled edge cases (null child nodes) ✔️ Calculated minimum depth correctly for uneven trees 💡 Key Insight: The minimum depth is the shortest path from the root node to a leaf node. We must handle cases where one subtree is missing — simply taking "min()" is not enough without checking null nodes. This problem improved my understanding of tree traversal and edge case handling in recursion 🌳 Learning to think deeper with trees every day 🔥💪 #LeetCode #Day43 #BinaryTree #DFS #Recursion #Python #ProblemSolving #CodingJourney #100DaysOfCode

Day 119 Same problem family, new constraint — but now it feels easier. #Day119 🧩 40. Combination Sum II How today went: • Very similar to Combination Sum • First step: sort the array • Move to i + 1 (each element used once) • Skip duplicates to avoid repeating combinations Key idea: 👉 No reuse of same element 👉 Handle duplicates carefully What I realized: Once you understand the base pattern, variants like this become much easier. Backtracking is starting to feel natural now. #LeetCode #DSA #Python #Backtracking #Recursion #LearningInPublic #Consistency

Day 117 Same pattern, one important tweak. #Day117 🧩 90. Subsets II How today went: • Same base as Subsets • First step: sort the array • While iterating, skip duplicates to avoid repeating subsets • Use the same pattern: append → recurse → pop What I learned: It’s not a new problem — it’s the same pattern with a duplicate filter. Small condition. Big impact. Backtracking is starting to feel predictable. #LeetCode #DSA #Python #Backtracking #Recursion #LearningInPublic #Consistency

Every dataset deserves a gentle first look 🌿 Today I’m starting with the basics: df.head(), df.info(), and df.describe() — the quiet steps that help you understand what you’re working with. And a tiny reminder: df.describe() shows only numeric columns, while df.describe(include="all") gives a fuller picture, including text and categories 📊 Day 1 is simply about seeing the story before we start cleaning ✨ #DataMom #OneMinuteDataCleaning #LearningJourney #DataCleaning #Pandas #Python #WomenInTech #MomsInTech #SustainableGrowth

🚀 LeetCode Grind: Find First and Last Position of Element in Sorted Array Just solved a classic searching problem! 💻 Problem: Given a sorted array, find the starting and ending position of a given target value. The Challenge: Achieving $O(\log n)$ runtime complexity. Key Takeaway: While a linear scan works, leveraging Binary Search twice (once for the left boundary and once for the right) is the key to meeting the performance constraints. It’s a great reminder of how powerful binary search is for optimizing search operations on sorted data. Checking off another one as I continue to sharpen my problem-solving skills! 🛠️ #LeetCode #CodingChallenge #Python #Algorithms #DataStructures #ProblemSolving #TechJourney #BinarySearch