m / n [terminology]

Terminology¶

Usage¶

Use n for the size of a one-dimensional sequence.
Use m and n for matrix dimensions:
- m: number of rows
- n: number of columns
Cache the size when it is used repeatedly or makes loop bounds clearer.

n = len(nums)
k %= n
if k == 0:
    return
# ...
reverse(0, n - 1)
reverse(0, k - 1)
reverse(k, n - 1)

See 189. Rotate Array.

m, n = len(mat), len(mat[0])
dist = [[-1] * n for _ in range(m)] # -1 means "not processed yet"
q = deque()
for r in range(m):
    for c in range(n):
        if mat[r][c] == 0:
            dist[r][c] = 0
            q.append((r, c))
# ...

See 542. 01 Matrix.