Cracking the Capital One Software Engineer Interview: Challenging String and Array Questions

capitalone | Software Engineer | Interview Experience

Interview Date: Not specified
Result: Not specified
Difficulty: Not specified

Interview Process

The interview consisted of two main coding questions. The first question involved string statistics, specifically counting occurrences of substrings within a given string. The candidate was required to split the string, count the occurrences, save the results in a list, and then sort the list to return the top two occurrences.

The second question involved an integer array and a modification constraint. The goal was to determine if, by modifying at most a specified number of elements in the array, all consecutive substrings could have a greatest common divisor (GCD) of 1. If not, the candidate was to find the maximum length of consecutive substrings where the GCD was greater than 1 after modifications.

Technical Questions

  1. String Statistics

    • Count occurrences of substrings in a string.
    • Return the two most frequent occurrences.
  2. GCD Modification Problem

    • Given an integer array and a modification limit, determine if all consecutive substrings can have a GCD of 1.
    • If not, find the maximum length of consecutive substrings with GCD > 1 after modifications.

Tips & Insights

The candidate noted that understanding the second problem took considerable time, approximately 40 minutes, to grasp the requirements. They suggested using a one-dimensional dynamic programming approach to find continuous GCDs greater than 1, while also considering the modification constraint to optimize the length of such substrings.