Classical Variable names

Abstract

Classical variable names used in solutions to the 48 problems of LeetCode Top Easy, with references to the types of problems or algorithms they are used for, and the reason for the name when it's not obvious.

These names are purposely limited to these problems.

Why these names matter:

Interviewers expect them.
They compress explanation.
They make standard patterns recognizable fast.

Generated with love by AI.

Array / two pointers¶

i, j: generic indices
left, right: opposite ends, two-pointer scans, palindrome, reverse, partition-ish work
read, write: in-place compaction problems (rationale: one pointer reads input, one writes kept values)
lo, hi: inclusive bounds in binary search / divide and conquer (rationale: short for low and high)
mid: middle index in binary search or recursive split
n,m, k: lengths or problem parameters (rationale: conventional short math-style names)

Hash map / set¶

seen: values already encountered
counts: frequency table
need: complement needed to complete a target, especially Two Sum

Linked list¶

head: first node of the list
dummy: fake node before head to simplify edge cases
cur: current node while traversing
prev: previous node or reversed prefix
nxt: saved next node before pointer rewrite
slow, fast: tortoise-hare or middle-finding pointers
tail: end of an output or merged list

Tree¶

root: top node
node: current node in DFS/BFS
left, right: child references
stack: iterative DFS
queue: BFS
depth: current tree depth

Dynamic programming / greedy¶

dp: dynamic programming table
cur, best: current local answer and global best
prev1, prev2: previous states in rolling DP
profit, min_price: stock problems
acc: accumulator, especially XOR accumulation

Bit manipulation¶

ans: result being built
digit: extracted decimal digit
count: bit count or loop count

Others¶

rows, cols, boxes: Sudoku constraint buckets