Elimination Game
A medium-tier problem at 45% community acceptance, tagged with Math, Recursion. Reported in interviews at Autodesk and 0 others.
Elimination Game is a medium-difficulty problem that shows up in Autodesk assessments and stumps candidates who try to simulate the elimination process. With a 45% acceptance rate, most people fail because they attempt to build arrays and iterate, running into time limits on large inputs. The trick isn't simulation. It's recognizing a mathematical pattern that lets you skip the whole elimination loop and compute the answer directly. If this problem hits your live OA and you blank on the pattern, StealthCoder surfaces the solution in seconds, invisible to the proctor.
Companies that ask "Elimination Game"
Elimination Game is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround.
Get StealthCoderThe naive approach is to simulate elimination: build a list, remove every other element, flip direction, repeat until one number remains. This works on small inputs but fails on large ones due to time and memory overhead. The real insight is mathematical: you can derive the survivor's position using recursion and bit manipulation, eliminating the simulation entirely. The key is tracking how the starting position and step size change each round, then computing backward to find the original position. Most candidates either don't see the pattern or implement it incorrectly. StealthCoder is your hedge for the live assessment if the recursion trick doesn't click under pressure.
Pattern tags
You know the problem.
Make sure you actually pass it.
Elimination Game recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Elimination Game interview FAQ
Why does the simulation approach fail?+
Simulating elimination for large n (e.g., n = 10^9) requires too much memory and time. You can't build and modify arrays that large. The problem demands a mathematical or recursive formula that skips simulation entirely and runs in O(log n) time.
What's the key insight?+
The survivor's position follows a recursive pattern. Each elimination round changes the starting position and step size. By tracking these changes and working backward, you can compute the final position without ever building or modifying a list.
Is this really asked in interviews?+
Yes. It appears in Autodesk assessments and similar companies that test math and recursion skills. The low 45% acceptance rate shows it's harder than it looks. Most candidates miss the pattern and time out.
How does recursion solve it?+
Define a recursive function that returns the survivor's position in the current round. Use the position and step size from the next round to compute the current one. Base case is a single element. This builds the answer without simulation.
What's the relationship between Math and Recursion here?+
The Math topic is the core. Recursion is the implementation vehicle. You need to recognize the mathematical pattern first, then express it recursively. Candidates who think recursion is the main topic often miss the actual math trick.
Want the actual problem statement? View "Elimination Game" on LeetCode →