MEDIUM NC#13 Blind #10 Two Pointers
11. Container With Most Water
📖 Problem
You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container contains the most water. Return the maximum amount of water a container can store. Notice that you may not slant the container.
🧠 Visual Learning Aid
1 Model the input into the right structure
2 Choose the core technique and invariant
3 Execute step-by-step with a sample
4 Validate complexity and edge cases
JS/TS Refreshers
- •Array methods (`push`, `pop`, `shift`, `slice`)
- •Object/Map/Set usage patterns
- •Function parameter and return typing
- •In-place array updates
- •Sorted array traversal
- •Boundary condition checks
Logical Thinking Concepts
- •Define invariants before coding
- •Check edge cases first (`[]`, single element, duplicates)
- •Estimate time/space before implementation
- •Apply Two Pointers reasoning pattern
💡 Approach
- → Use two pointers at both ends
- → Area = min(height[left], height[right]) * (right - left)
- → Move the pointer with smaller height inward
- → The goal is to find taller lines that are farther apart
- → Time: O(n), Space: O(1)
🧭 Prerequisites
🛠️ Hints & Pitfalls
Hints
- •Use two pointers at both ends
- •Area = min(height[left], height[right]) * (right - left)
- •Move the pointer with smaller height inward
Common Pitfalls
- •The goal is to find taller lines that are farther apart
- •Time: O(n), Space: O(1)
🧪 Test Cases
Hidden tests on submit: 2
Test Case 1
Not run Input:
maxArea([1,8,6,2,5,4,8,3,7]); Expected:
49 Test Case 2
Not run Input:
maxArea([1,1]); Expected:
1 Test Case 3
Not run Input:
maxArea([4,3,2,1,4]); Expected:
16 📝 Code Editor
📤 Output