Core Insight Name the mathematical relationship first, then apply it consistently to every position or digit.
Common Pitfall Write down index and boundary conditions before mutating an in-place structure.
Description
Return all elements of a matrix in spiral order.
Constraints
- Time Complexity:
O(n²) - Space Complexity:
O(n²)
Tags
arraymatrixsimulation
Implementation Plan Translate the invariant into these small, testable moves.
- Identify the formula or transformation.
- Set boundary conditions.
- Process each required position.
- Return the transformed result.
def spiralOrder(matrix):
res = []
left, right = 0, len(matrix[0])
top, bottom = 0, len(matrix)
while left < right and top < bottom:
for i in range(left, right):
res.append(matrix[top][i])
top += 1
for i in range(top, bottom):
res.append(matrix[i][right - 1])
right -= 1
if not (left < right and top < bottom):
break
for i in range(right - 1, left - 1, -1):
res.append(matrix[bottom - 1][i])
bottom -= 1
for i in range(bottom - 1, top - 1, -1):
res.append(matrix[i][left])
left += 1
return res