Leetcode #2545: Sort the Students by Their Kth Score

In this guide, we solve Leetcode #2545 Sort the Students by Their Kth Score in Python and focus on the core idea that makes the solution efficient.

You will see the intuition, the step-by-step method, and a clean Python implementation you can use in interviews.

Problem Statement

There is a class with m students and n exams. You are given a 0-indexed m x n integer matrix score, where each row represents one student and score[i][j] denotes the score the ith student got in the jth exam.

Quick Facts

• Difficulty: Medium
• Premium: No
• Tags: Array, Matrix, Sorting

Intuition

Sorting reveals structure that is hard to see in the original order.

Once sorted, a linear scan is usually enough to compute the answer.

Approach

Sort the data and sweep through it while maintaining a small state.

This keeps the logic straightforward and reliable.

Steps:

• Sort the data.
• Scan in order while maintaining state.
• Update the best answer.

Example

Python Solution

Complexity

The time complexity is $O(m \times \log m)$, and the space complexity is $O(\log m)$. The space complexity is $O(\log m)$.

Edge Cases and Pitfalls

Watch for boundary values, empty inputs, and duplicate values where applicable. If the problem involves ordering or constraints, confirm the invariant is preserved at every step.

Summary

This Python solution focuses on the essential structure of the problem and keeps the implementation interview-friendly while meeting the constraints.