LeetCode Medium Problems 75

(a.k.a. Welcome to the Algorithm Hunger Games)

Now that you’ve survived Easy mode, it’s time to enter Medium — the level where your code works on sample tests only.

Medium problems are like business meetings:

• Everyone looks calm,

• But deep down, nobody knows what’s happening.

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⚔️ What “Medium” Really Means

You’ll meet algorithms with names like “Dynamic Programming,” “Sliding Window,” and “Backtracking.” Each one sounds like a yoga pose but feels like a mild existential crisis.

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🧩 Classic Medium Problems

Problem	Concept	Comedy Summary
3Sum	Two pointers	“The sequel to Two Sum — now featuring drama.”
Add Two Numbers (Linked Lists)	Linked list arithmetic	“Because normal addition was too mainstream.”
Group Anagrams	Hash maps	“Because spelling is hard — even for computers.”
Longest Substring Without Repeating Characters	Sliding window	“Teaches you commitment issues.”
Binary Tree Level Order Traversal	BFS	“A data structure family reunion.”
Kth Smallest Element in a BST	In-order traversal	“Counting leaves like it’s autumn.”
Word Search	Backtracking	“Hide-and-seek for letters — exhausting but fun.”
Combination Sum	Recursion	“The mathematical buffet problem: take everything that fits.”
Top K Frequent Elements	Heap	“Who are the influencers of your array?”

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🧠 Medium Survival Tips

1. Draw things. Half the time, your brain just wants a picture.

2. Name your variables properly. x, xx, and xxx aren’t debugging-friendly.

3. Expect failure. If your first submission passes, check if you’re dreaming.

4. Read solutions, not to copy — but to steal wisdom.

Pro Tip: Medium problems are like dating — the key is consistency, not speed.

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“Medium isn’t about difficulty. It’s about humility.” 😇

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# Your code here