Maximum Population Year
A easy-tier problem at 63% community acceptance, tagged with Array, Counting, Prefix Sum. Reported in interviews at Zoho and 1 others.
Maximum Population Year is the kind of problem that looks trivial on the surface, then trips up candidates who overthink it. You're given birth and death years, and you need to find which year had the most people alive. It appears frequently in Zoho and PayPal assessments. The acceptance rate sits around 63%, which tells you most people solve it, but there's a speed and clarity gap. If you blank on the sweep-line trick during your OA, StealthCoder surfaces the working solution invisibly so you move on without panic.
Companies that ask "Maximum Population Year"
Maximum Population Year 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 an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too.
Get StealthCoderThe naive approach is looping through every year and counting overlaps, which works for small ranges but tanks on large year spans. The real pattern is coordinate compression or a sweep-line counter: increment at birth years, decrement at death years, then scan the deltas to find the peak. Many candidates waste time on arrays or hashmaps when a simple sorted-key pass does it. The trap is overthinking the data structure; you don't need to simulate every single year. If this problem hits your live assessment and you freeze on the algorithm, StealthCoder runs invisibly and hands you a working sweep-line or prefix-sum solution in seconds, keeping you on pace.
Pattern tags
You know the problem.
Make sure you actually pass it.
Maximum Population Year recycles across companies for a reason. It's easy-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 an Amazon engineer who watched the leaked-problem repo become an industry secret. He decided you should have it too. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Maximum Population Year interview FAQ
Is this problem actually easy?+
Yes, the 63% acceptance rate confirms it. But 'easy' means easy to solve, not fast to code under pressure. The trick is recognizing the sweep-line pattern. Without it, you write slow code that passes small test cases and fails large ones. That's where the 37% of failures live.
Do Zoho and PayPal really ask this?+
Yes, both companies appear in the verified problem report. Zoho especially uses it in their online assessments. It's not the only problem you'll see, but if population-counting variants show up in your prep, this is the canonical version.
What's the trick I'm supposed to spot?+
Treat it as an event-based problem, not a year-by-year simulation. Mark each birth as a +1 event and each death as a -1 event. Sort by year, apply the deltas in order, track the max. This avoids iterating through every year in a potentially huge range.
Should I use a prefix sum?+
It's one valid approach. You can think of prefix sums as pre-computing cumulative events across sorted years. It's elegant and fast. A simpler event-sweep (just tracking current population as you process events) also works and is faster to code in an interview.
What if I get a Time Limit Exceeded?+
You're looping through every year in the range instead of just the event years. Drop the year-by-year iteration. Use only the birth and death years that appear in your input, sort them, apply deltas, find the max. That alone fixes TLE for this problem.
Want the actual problem statement? View "Maximum Population Year" on LeetCode →