Binary Search/Kth Smallest Element in a Sorted MatrixMedium

This practice workspace is built for desktop. Open it on a larger screen to start solving.

Kth Smallest Element in a Sorted Matrix

Binary Search·Medium

Given an n x n matrix where each of the rows and columns is sorted in ascending order, return the k-th smallest element in the matrix.

Note that it is the k-th smallest element in the sorted order, not the k-th distinct element.

You must find a solution with a memory complexity better than O(n^2).

Examples

Input: matrix = [[1,5,9],[10,11,13],[12,13,15]], k = 8

Output: 13

The elements in sorted order are [1,5,9,10,11,12,13,13,15], and the 8th smallest is 13.

Input: matrix = [[-5]], k = 1

Output: -5

n == matrix.length == matrix[i].length
1 <= n <= 300
-10^9 <= matrix[i][j] <= 10^9
All the rows and columns of matrix are guaranteed to be sorted in non-decreasing order.
1 <= k <= n^2

00:00Preview Mode (Read Only)

Loading editor…

Tests

Preview Mode

This is a read-only preview of DSAMind's AI coaching. Sign up to get custom feedback on your own solution.

Passed32 ms

First attempt — retry to track metric movement here.

Complete approach — pattern and complexity both named.

You correctly matched the sorted input requirement and implemented a linear-time scan using two pointers.

No divergence detected. The code correctly aligns with the stated approach.

Try solving related sliding window problems to build familiarity with two-pointer variants.

No signals fired — clean run, you stayed in flow.