l / r [terminology]

Terminology¶

Usage¶

• Use for moving left and right indices or pointers.
• Common uses include:
  • Two-pointer scans
  • Sliding windows
  • Binary search over sequence positions
  • Recursive boundaries that move inward
• Prefer left and right when several directional concepts coexist or the scope is large.

l, r = 0, len(s) - 1
while l < r:
    s[l], s[r] = s[r], s[l]
    l += 1
    r -= 1

See 344. Reverse String.