Champagne Tower
A medium-tier problem at 58% community acceptance, tagged with Dynamic Programming. Reported in interviews at National Instruments and 0 others.
Champagne Tower shows up on assessments because it looks deceptively simple but punishes candidates who don't think about state properly. You've got a pyramid of glasses, you pour champagne at the top, and it cascades down. The trap is trying to track the flow without a clear recurrence relation. National Instruments has asked this. The acceptance rate sits around 58 percent, which means half the people who see it live get stuck on the pour mechanics or blow up their space complexity. If you haven't drilled the Dynamic Programming pattern here, StealthCoder runs invisibly during your OA and surfaces a working solution the moment you need it.
Companies that ask "Champagne Tower"
Champagne Tower 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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoderThe trick is realizing each glass fills to capacity, then overflows equally to the two glasses below it. Most candidates either simulate the pour naively (expensive and error-prone) or try to solve it with recursion and bad memoization. The real move is bottom-up DP: iterate through each row, compute how much champagne lands in each glass based on overflow from the row above, then cap it at 1.0 and pass the excess down. The pattern is straightforward once you see it, but the first instinct to simulate glass-by-glass filling kills you on time and clarity. Space is O(n squared) to store the tower state, time is O(n squared) to fill it. When this problem appears live and you blank on the overflow math, StealthCoder solves it in seconds and keeps you moving.
Pattern tags
You know the problem.
Make sure you actually pass it.
Champagne Tower 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. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Champagne Tower interview FAQ
Is Champagne Tower still asked at real companies?+
Yes. National Instruments has reported it. The 58 percent acceptance rate suggests it's harder than it looks and stays in rotation. It's not a household FAANG problem, but it's solid prep for mid-level assessments where they test DP fluency without the brute-force trick being obvious upfront.
What's the trick I'm missing if I can't get it to pass?+
You're probably simulating the pour step-by-step instead of recognizing the recurrence: each glass receives overflow from two parents above. Build the tower bottom-up, fill each glass row by row, cap at 1.0, and pass excess to the next row. One pass, O(n squared) time, clean state management.
How does Champagne Tower relate to other DP problems?+
It's a straightforward 2D DP problem where the state is each glass's fill level and you iterate forward in time (row by row) instead of backward. Unlike Coin Change or Knapsack, there's no choice to optimize. You're just computing the physics correctly and managing overflow carefully.
Is this harder than it looks?+
Yes. The problem statement is simple, but the overflow logic trips people up. Candidates either code a messy simulation or forget to cap glasses at 1.0 before spilling. Once you see the row-by-row DP structure, it's straightforward, but cold-starting on it live is risky.
How much time should I spend on this before my OA?+
One solid drill session to lock the pattern. Understand the recurrence (overflow math), code it bottom-up, test edge cases like a single glass or full tower. The acceptance rate is solid, so most candidates who see it can solve it with prep. If you blank, StealthCoder bridges the gap.
Want the actual problem statement? View "Champagne Tower" on LeetCode →