Find the Kth Largest Integer in the Array
Problem Statement
You are given an array nums of strings. Each string is a whole number written in digits. A number can have up to 100 digits, so it can be too big for any C++ integer type. No number has leading zeros.
Return the kth largest number, as a string. Equal numbers count as separate positions, as they do in Kth Largest Element in an Array.
nums, an array of digit strings, and k.
The kth largest number, as a string.
Sorted from biggest: 10, 7, 6, 3. The 4th is 3. The number 10 is bigger than 7, even though it starts with 1.
Sorted from biggest: 21, 12, 2, 1. The 3rd is 2.
Both numbers are 0. Equal numbers still take separate positions, so the 2nd largest is 0.
- • 1 ≤ k ≤ nums.length ≤ 10^4
- • 1 ≤ nums[i].length ≤ 100
- • nums[i] consists of only digits
- • nums[i] will not have any leading zeros
Pattern Recognition Clues
Recognising these key signals in the problem description immediately identifies the pattern:
Approach Complexity Ladder
Sort biggest first, comparing length before text, then return index k − 1
Keep the k largest numbers in a min-heap; its top is the kth largest
Sort nums from biggest to smallest. The comparator checks length first, then the text. After that, nums[k − 1] is the answer.
Recognition rule for this sub-pattern:
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How this concept connects to System Design & C++ Systems
Top engineering interviews test whether you understand how algorithms like Heap — Top K translate into production architectures and low-level memory mechanics.