Meeting Rooms III
A hard-tier problem at 44% community acceptance, tagged with Array, Hash Table, Sorting. Reported in interviews at Pinterest and 4 others.
Meeting Rooms III is the hard-level follow-up that trips up candidates who breeze through the first two. You're managing meeting room assignments and tracking which room gets used next, which sounds simple until you realize you need to simulate the entire schedule and track room availability across multiple dimensions. Pinterest, Google, Uber, and TikTok have all asked this. The acceptance rate sits at 44%, which means half the people who attempt it don't ship. If this hits your live OA and you're unsure whether to simulate forwards or use a heap, StealthCoder surfaces the working approach in seconds, invisible to the proctor.
Companies that ask "Meeting Rooms III"
Meeting Rooms III 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 Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE.
Get StealthCoderThe trap is thinking you can solve this greedily without simulation. You can't. You need to process meetings in order, track when each room becomes free, and assign the next meeting to the room that finishes earliest. A heap (priority queue) holding room availability times is the core. Most candidates either build the heap wrong, forget to handle tie-breaking (assign to the room with the lowest index if two rooms free up at the same time), or simulate inefficiently. Array, Hash Table, and Sorting all play supporting roles: you sort by meeting start time, use a heap to track room states, and may hash room IDs. If you've drilled heap-based scheduling before, the pattern clicks fast. If not, you'll spend 20 minutes debugging. StealthCoder hedges the case where the trick doesn't surface during the interview.
Pattern tags
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Make sure you actually pass it.
Meeting Rooms III recycles across companies for a reason. It's hard-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 Amazon engineer who got tired of watching qualified friends bomb OAs they'd solve cold in an IDE. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Meeting Rooms III interview FAQ
Is Meeting Rooms III actually asked at big tech companies?+
Yes. Google, TikTok, Uber, Pinterest, and PayPal have all reported asking it. It's a core scheduling problem. The 44% acceptance rate tells you it's genuinely hard, not just a routine heap question. If you're prepping for those companies, this pattern will show up.
What's the actual trick to this problem?+
Simulate the meetings chronologically and use a min-heap to track which room finishes earliest. Assign each new meeting to that room. Handle ties by picking the room with the lowest index. The heap state updates after each meeting assignment. Most people overthink it or forget the tie-break rule.
Can I solve this without a heap?+
Technically, yes, but it's inefficient. You could re-scan the room list for each meeting, but with large inputs that's O(n*m) time. A heap keeps it O(n log m), where m is the number of rooms. The heap approach is the expected solution.
How does Meeting Rooms III differ from the first two versions?+
Rooms I is just overlap detection. Rooms II counts the minimum rooms needed. Rooms III forces you to actually simulate and track which specific room each meeting gets. You're building a room assignment, not just counting or overlapping. Simulation and heap are required.
Is this really a hard problem or does it just feel hard?+
It's genuinely hard because the simulation logic, heap management, and tie-break rule all need to work together. The 44% acceptance rate isn't inflated. Most failures come from getting the heap update or tie-break wrong, not misunderstanding the premise.
Want the actual problem statement? View "Meeting Rooms III" on LeetCode →