Largest Plus Sign
A medium-tier problem at 49% community acceptance, tagged with Array, Dynamic Programming. Reported in interviews at Intuit and 0 others.
Largest Plus Sign is a medium-difficulty array and dynamic programming problem that shows up in Intuit assessments. You're given an array of 0s and 1s and need to find the largest plus sign you can form using only 1s. Most people see it as a geometry problem and overthink the indexing. The real trick is that you can't just scan and measure in one pass. This is exactly the kind of problem where the pattern doesn't hit you immediately during a live OA, but it's solvable once you know the approach. If you blank on it, StealthCoder surfaces a working solution in seconds while your screen stays clean.
Companies that ask "Largest Plus Sign"
Largest Plus Sign 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 by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoderThe problem requires you to find the largest plus sign centered at each position, where a plus of 'order k' has k 1s extending left, right, up, and down from a center point. The naive approach is checking all four directions for every cell, which gets expensive fast. The efficient path uses dynamic programming to precompute four tables: the max consecutive 1s extending left from each cell, right from each cell, up from each cell, and down from each cell. Then at each position, the largest plus is limited by the minimum of those four values. Most candidates either miss the DP optimization entirely or mess up boundary handling in one direction. This problem tests both algorithmic thinking and careful implementation. StealthCoder handles the precomputation logic and the final sweep when you're stuck on direction or indexing bugs during the assessment.
Pattern tags
You know the problem.
Make sure you actually pass it.
Largest Plus Sign 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 by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Largest Plus Sign interview FAQ
Is this problem still asked at Intuit and similar companies?+
Yes. It appears in Intuit's assessments and similar companies use geometry-and-DP hybrid problems regularly. It's not the most common, but it's common enough that you can't skip it. The acceptance rate is around 49%, so it's genuinely tricky even for experienced candidates.
What's the trick that separates passing from failing?+
Realizing you need four precomputation passes, not one. Building tables for left-to-right, right-to-left, top-to-bottom, and bottom-to-top consecutive 1s. Then the answer at each cell is the minimum of those four values. Without DP, you time out. With it, you're O(n*m) time and space.
How does this relate to the Dynamic Programming topic?+
It's a directional DP problem. You're building up state in multiple directions simultaneously and combining them. It's similar to max-subarray or house-robber patterns, but you're thinking in four directions instead of one, which requires careful bookkeeping and multiple passes.
What's the most common mistake candidates make?+
Forgetting that the plus sign's order is constrained by all four directions equally. You can't have a plus of order 3 if there are only 2 ones to the left. Boundary off-by-one errors are also brutal here because you're tracking extends in four separate passes with different loop directions.
Do I need to memorize the exact DP table structure?+
You don't need to memorize it, but you do need to nail the pattern: four 2D arrays, each tracking the max extend of 1s in one direction from each cell. The implementation is straightforward once you see it, which is why this is a perfect problem for StealthCoder to handle live if the structure escapes you during the real assessment.
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