Determine whether a word exists in a letter grid
Company: Atlassian
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
Given an `m x n` grid of characters `board` and a string `word`, determine whether `word` can be constructed from sequentially adjacent cells.
Rules:
- Adjacent cells are those horizontally or vertically neighboring (no diagonals).
- The same cell may not be used more than once in a single construction path.
#### Input
- `board`: 2D array of characters
- `word`: target string
#### Output
- Return `true` if `word` exists in the grid by the rules above, else `false`.
#### Example
`board = [[A,B,C,E],[S,F,C,S],[A,D,E,E]]`, `word = "ABCCED"` → `true`
#### Constraints
- `1 ≤ m, n ≤ 12`
- `1 ≤ |word| ≤ m*n`
Quick Answer: This question evaluates algorithmic problem-solving and implementation skills in grid-based search, including concepts like graph traversal and backtracking; it falls under Coding & Algorithms and primarily assesses practical application and state-management implementation rather than only conceptual understanding.