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 hard difficulty Coding & Algorithms question, commonly asked during Technical Screen rounds at Snowflake.

What role is this question designed for?

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

Solve scheduling and tree path problems | Snowflake Interview Question

Q: Solve scheduling and tree path problems

This set evaluates interval scheduling and constrained optimization for weighted, at-most-K selection, tree structure manipulation and subtree effects on height, and tree pathfinding with parent/child navigation, testing competencies in dynamic programming-like optimization, data structures (trees/binary trees), traversal, and ancestor relationships. These problems are commonly asked in Coding & Algorithms interviews because they probe algorithmic efficiency and correctness under large constraints and require both conceptual understanding of algorithmic trade-offs and practical implementation skills.

You are given three separate coding problems (asked across two rounds). For each, write a function that returns the required output.

Problem 1: Max credits with at most K non-overlapping courses

You are given n courses. Course i has:

start time s[i]
end time e[i] (assume a course occupies the half-open interval [s[i], e[i]) so a course ending at time t does not conflict with another starting at t )
credit value c[i]

You may take at most K courses, and you may not take overlapping courses.

Output: the maximum total credits you can earn.

Inputs: arrays s, e, c and integer K.

Constraints (assume typical interview ranges): 1 ≤ n ≤ 2e5, 1 ≤ K ≤ n, times up to 1e9, credits up to 1e9.

Problem 2: Height of a rooted tree after deleting a node (subtree removal)

You are given a rooted binary tree (or general rooted tree—state assumptions in your solution) and a node x.

Operation: remove node x and its entire subtree from the tree.

Output: the height of the remaining tree (define height as number of edges on the longest path from the root to any remaining node; height of an empty tree is -1 or 0—state your convention).

You may be asked to answer this for one query or for multiple queries.

Problem 3: Directions between two nodes in a binary tree

You are given a binary tree and two node values startValue and destValue.

You must output a string describing how to move from the startValue node to the destValue node using:

L : move to left child
R : move to right child
U : move to parent

Output: the direction string representing a valid shortest path from start to destination.

You are given three separate coding problems (asked across two rounds). For each, write a function that returns the required output.

Problem 1: Max credits with at most K non-overlapping courses

You are given n courses. Course i has:

start time s[i]
end time e[i] (assume a course occupies the half-open interval [s[i], e[i]) so a course ending at time t does not conflict with another starting at t )
credit value c[i]

You may take at most K courses, and you may not take overlapping courses.

Output: the maximum total credits you can earn.

Inputs: arrays s, e, c and integer K.

Constraints (assume typical interview ranges): 1 ≤ n ≤ 2e5, 1 ≤ K ≤ n, times up to 1e9, credits up to 1e9.

Problem 2: Height of a rooted tree after deleting a node (subtree removal)

You are given a rooted binary tree (or general rooted tree—state assumptions in your solution) and a node x.

Operation: remove node x and its entire subtree from the tree.

You may be asked to answer this for one query or for multiple queries.

Problem 3: Directions between two nodes in a binary tree

You are given a binary tree and two node values startValue and destValue.

You must output a string describing how to move from the startValue node to the destValue node using:

L : move to left child
R : move to right child
U : move to parent

Output: the direction string representing a valid shortest path from start to destination.

Solve scheduling and tree path problems

Quick Overview

Problem 1: Max credits with at most K non-overlapping courses

Problem 2: Height of a rooted tree after deleting a node (subtree removal)

Problem 3: Directions between two nodes in a binary tree

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Solve scheduling and tree path problems

Quick Overview

Problem 1: Max credits with at most K non-overlapping courses

Problem 2: Height of a rooted tree after deleting a node (subtree removal)

Problem 3: Directions between two nodes in a binary tree

Comments (0)