Max Chunks To Make Sorted
A medium-tier problem at 64% community acceptance, tagged with Array, Stack, Greedy. Reported in interviews at Poshmark and 0 others.
Max Chunks To Make Sorted hits your OA, and you've got maybe 25 minutes to nail it. It's a medium, 64% acceptance rate, but the naive greedy approach fails hard once you stop thinking in terms of swaps. The pattern is: figure out how many independent segments of the array you can sort separately and still get a globally sorted result. Poshmark asks it. If you blank on the monotonic stack trick during your assessment, StealthCoder runs invisibly and surfaces a working solution in seconds, leaving you time to move on.
Companies that ask "Max Chunks To Make Sorted"
Max Chunks To Make Sorted 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 StealthCoderMost candidates try to greedily chunk whenever the current max is in the right place, but that's fragile. The real insight: chunk at position i if and only if the max of array[0..i] equals i. That works for the simple case. For the harder variant, you need to track what values are actually required in each potential chunk using a monotonic stack to avoid creating chunks that can't be internally sorted. When the obvious greedy scan doesn't work, the stack-based approach maintains invariants about which elements must stay together. This is where most interviews fall apart. During the live OA, if you're spinning on whether your chunk boundaries are valid, StealthCoder provides the correct segmentation instantly.
Pattern tags
You know the problem.
Make sure you actually pass it.
Max Chunks To Make Sorted 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.
Max Chunks To Make Sorted interview FAQ
Is the greedy max-equals-index trick actually enough?+
For the basic version, yes. For harder variants with arbitrary permutations, no. The greedy chunk works if max(arr[0..i]) equals i at that index. But once elements are shuffled, you need a monotonic stack to ensure each chunk's internal elements can be sorted without crossing boundaries.
How does this relate to sorting and greedy?+
Greedy picks the earliest valid chunk boundary. Sorting is implicit: you're not actually sorting, just proving that chunks CAN be sorted independently. The trick is recognizing which boundaries are valid without doing any actual sort operations.
Why does Poshmark ask this?+
It filters for candidates who understand monotonic data structures and greedy partitioning. You need both greedy intuition and the ability to validate chunk boundaries efficiently, which Poshmark values in backend work.
What's the time complexity and does it matter?+
Single-pass greedy is O(n), monotonic stack approach is also O(n). Your answer needs to be linear or you'll fail the medium cases. Space is O(n) worst case for the stack, but that's acceptable.
Will I see this on other OAs or just Poshmark?+
It's a niche problem, but the pattern (greedy chunking plus stack validation) appears in partition and segmentation problems across platforms. Master it once, reuse the intuition.
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