MEDIUM NC#137 Blind #47 Math & Geometry - Simulation

54. Spiral Matrix

📖 Problem

Given an m x n matrix, return all elements of the matrix in spiral order (clockwise, starting from top-left corner).

🧠 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

Logical Thinking Concepts

  • •Define invariants before coding
  • •Check edge cases first (`[]`, single element, duplicates)
  • •Estimate time/space before implementation
  • •Apply Recursion reasoning pattern

💡 Approach

  • → Use four pointers: top, bottom, left, right
  • → Traverse in order: left→right (top), top→bottom (right),
  • → After each traversal, move the corresponding pointer inward
  • → Time: O(m * n), Space: O(1) excluding output

🛠️ Hints & Pitfalls

Hints

  • •Use four pointers: top, bottom, left, right
  • •Traverse in order: left→right (top), top→bottom (right),
  • •After each traversal, move the corresponding pointer inward

Common Pitfalls

  • •Time: O(m * n), Space: O(1) excluding output

🧪 Test Cases

Test Case 1
Not run
Input:
spiralOrder([[1,2,3],[4,5,6],[7,8,9]]);
Expected:
[1, 2, 3, 6, 9, 8, 7, 4, 5]
Test Case 2
Not run
Input:
spiralOrder([[1,2,3,4],[5,6,7,8],[9,10,11,12]]);
Expected:
[1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7]
Test Case 3
Not run
Input:
spiralOrder(matrix: number[][]);
Expected:
Computed from hidden reference

📝 Code Editor

📚 Reference Solution

▼
⌘K Search ⌘↩ Run ⌘S Submit