Phase 01
Python Foundations
Fluency in the language you solve in.
Skill Coverage
LEETCODELOCK IN
Stop memorizing solutions. Learn how to think through every problem, pattern by pattern.
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Easy1. Two Sum
Given an array of integers nums and an integer target, return indices of the two numbers that add up to target.
1
Python 3
LeetLockin Tutor
Pattern
Hash Map
Store each complement as a key. One pass, look up before you insert.
Complexity
O(n) time · O(n) space
Optimal. Single pass through the array.
Accepted
Runtime: 52ms · Beats 98.4% of submissions
You arrived at the answer yourself.
That's what makes it stick.
Curriculum
From zero to
interview-ready.
Phase 02
Core Data Structures
The toolkit every problem is built from.
Skill Coverage
Phase 03
Pattern Library
Recognize the shape of any problem.
Skill Coverage
Phase 04
Interview Ready
Timed mocks. Company-specific sets.
Skill Coverage
How It Works
A system, not a
pile of problems.
Step 01
3
1
4
1
5
9
2
6
Sliding window
Learn the Pattern
Before you touch a problem, you learn the framework behind it. Sliding window. Two pointers. Hash maps. Understand why each pattern exists and when to reach for it.
Step 02
1
3
5
7
9
11
13
15
L
R
Two pointers
Solve with Guidance
Progressive hints move your thinking forward: broad to specific to concrete. You arrive at the answer yourself. That's what makes it actually stick.
Step 03
'apple'
→3
'banana'
→1
'cherry'
→5
'date'
→2
Hash map
Master the Pattern
Track which patterns you've internalized. Problems stop feeling random and start feeling familiar. One pattern unlocks dozens of problems.
Pricing
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Start understanding.
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