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.

What difficulty level is this interview question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Meta.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Meta during technical interviews.

Implement cd and merge intervals | Meta Interview Question

Q: Implement cd and merge intervals

This question evaluates proficiency in filesystem path normalization (string parsing, tokenization, and edge-case handling) and interval-merging algorithms (sorting, range consolidation, and handling overlaps), testing skills in string manipulation, data structures, and algorithmic reasoning.

Problem 1: Implement a simplified `cd` command

You are given:

cwd : the current working directory as an absolute Unix path (starts with / ).
path : a target path that may be absolute (starts with / ) or relative.

Implement the behavior of a simplified Linux cd command and return the resulting normalized absolute path.

Normalization rules:

. means “stay in the same directory”.
.. means “go to parent directory” (if already at / , stay at / ).
Multiple consecutive slashes should be treated as a single separator.
The output must:
- start with /
- not end with / unless the path is exactly /

Input: cwd (string), path (string)

Output: normalized absolute path (string)

Examples

cwd = "/a/b" , path = "../c" → "/a/c"
cwd = "/" , path = "../../x" → "/x"
cwd = "/a/b" , path = "/d//e/./f/.." → "/d/e"

Problem 2: Merge overlapping intervals

You are given a list of intervals intervals, where each interval is [start, end] (inclusive) and start <= end.

Merge all intervals that overlap and return a list of the merged, non-overlapping intervals that cover the same ranges.

Two intervals overlap if they share any point, i.e., [a, b] and [c, d] overlap when c <= b.

Input: intervals: List[List[int]]

Output: merged intervals (in any order, or sorted by start—specify which you choose)

Examples

[[1,3],[2,6],[8,10],[15,18]] → [[1,6],[8,10],[15,18]]
[[1,4],[4,5]] → [[1,5]]

Constraints (typical):

1 <= len(intervals) <= 10^5
interval endpoints fit in 32-bit integers

Problem 1: Implement a simplified `cd` command

You are given:

cwd : the current working directory as an absolute Unix path (starts with / ).
path : a target path that may be absolute (starts with / ) or relative.

Implement the behavior of a simplified Linux cd command and return the resulting normalized absolute path.

Normalization rules:

. means “stay in the same directory”.
.. means “go to parent directory” (if already at / , stay at / ).
Multiple consecutive slashes should be treated as a single separator.
The output must:
- start with /
- not end with / unless the path is exactly /

Input: cwd (string), path (string)

Output: normalized absolute path (string)

Examples

cwd = "/a/b" , path = "../c" → "/a/c"
cwd = "/" , path = "../../x" → "/x"
cwd = "/a/b" , path = "/d//e/./f/.." → "/d/e"

Problem 2: Merge overlapping intervals

You are given a list of intervals intervals, where each interval is [start, end] (inclusive) and start <= end.

Merge all intervals that overlap and return a list of the merged, non-overlapping intervals that cover the same ranges.

Two intervals overlap if they share any point, i.e., [a, b] and [c, d] overlap when c <= b.

Input: intervals: List[List[int]]

Output: merged intervals (in any order, or sorted by start—specify which you choose)

Examples

[[1,3],[2,6],[8,10],[15,18]] → [[1,6],[8,10],[15,18]]
[[1,4],[4,5]] → [[1,5]]

Constraints (typical):

1 <= len(intervals) <= 10^5
interval endpoints fit in 32-bit integers

Implement cd and merge intervals

Quick Overview

Problem 1: Implement a simplified `cd` command

Problem 2: Merge overlapping intervals

Submit Your Answer to Earn 20XP

Implement cd and merge intervals

Quick Overview

Problem 1: Implement a simplified `cd` command

Problem 2: Merge overlapping intervals

Submit Your Answer to Earn 20XP

Implement cd and merge intervals

Quick Overview