capitalone | Software Engineer | Interview Experience
Interview Date: Not specified
Result: Not specified
Difficulty: Not specified
Interview Process
The interview was conducted on the CodeSignal platform, lasting 70 minutes and consisting of 4 coding problems.
Technical Questions
-
Toggle Case of String
Implement a function that takes a string and returns a new string with each letter’s case toggled (uppercase to lowercase and vice versa). Non-letter characters should remain unchanged.- Input: “Hello, World!”
- Output: “hELLO, wORLD!”
- Time Complexity: O(n)
-
Simplified cd Command
Given a series of commands starting from the root directory/, return the final absolute path after executing the commands.- Input: commands = [“cd users”, “cd codesignal”, “cd ..”]
- Output: “/users”
-
Moisture Grid Smoothing
Given a 2D matrix representing soil moisture and an integer smoothing radius, update each cell’s moisture value based on the average of its neighbors within the radius.- Input: moistureGrid = [[9, 6], [3, 0]], smoothingRadius = 1
- Output: [[6, 5], [4, 3]]
- Time Complexity: O(n*m)
-
Largest Square in Histogram (Cityline)
Given an array representing the heights of bars in a histogram, find the area of the largest square that can fit within the histogram.- Input: [1, 2, 3, 2, 1]
- Output: 4 (side length = 2, area = 2²)
- Time Complexity: O(n)
Tips & Insights
Focus on understanding the problem requirements clearly and managing edge cases effectively. Practice coding under timed conditions to improve speed and accuracy.