Solve common string/tree/grid interview tasks

Q: Solve common string/tree/grid interview tasks

This problem set evaluates practical coding competencies including string parsing and sign handling, positional and frequency-based matching for feedback scoring, grid pathfinding via backtracking traversal, and binary-tree vertical ordering using column indices and level-order traversal, testing data structure knowledge (arrays, hash maps, trees) and algorithmic techniques (search, traversal, and counting). It is commonly asked in the Coding & Algorithms domain to measure correctness on edge cases, handling of duplicates and positional constraints, and implementation efficiency; the tasks are primarily practical implementation problems that also require conceptual understanding of algorithmic trade-offs and traversal strategies.

Q: How do I approach Coding & Algorithms interview questions?

Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

Question

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Problem Set (solve all in one interview)

1) Parse an integer from a string ("atoi"-style)

Implement a function:

parseInt(s: string) -> int

Given a string s representing a base-10 integer, return its integer value.

Assumptions (make explicit during interview):

s may contain an optional leading + or - .
s contains only digits after the optional sign (no decimals).
If the format is invalid, you may either return 0 or throw/return an error value (state your choice).

Examples

"123" -> 123
"-45" -> -45

2) Compute Wordle-style feedback for a guess

Implement a function:

scoreWordle(guess: string, target: string) -> string

Both strings have the same length n. Return a result string of length n where each position indicates:

G (green): guess[i] == target[i]
Y (yellow): guess[i] occurs in target but not at position i , and the occurrence is not already “used up” by other matches (i.e., handle duplicates correctly)
B (black/gray): the letter does not occur in the remaining unused letters of target

Example

guess = "allee", target = "apple" -> "GYBYB"

3) Word path in a grid

Given an m x n grid of characters board and a string word, determine if word can be formed by a path in the grid.

Rules:

You may move up/down/left/right.
You cannot use the same cell more than once in the same path.

Return true if the word exists, else false.

4) Vertical order traversal of a binary tree

Given the root of a binary tree, return its vertical order traversal:

Group nodes by their column index (root at column 0 , left child -1 , right child +1 ).
Output columns from leftmost to rightmost.
Within the same column, list nodes from top to bottom; if two nodes share the same row and column, order them left-to-right as encountered in a level-order traversal.

Return a list of columns, e.g. [[col-2 nodes], [col-1 nodes], ..., [col+2 nodes]].