Number of Adjacent Elements With the Same Color
A medium-tier problem at 56% community acceptance, tagged with Array. Reported in interviews at Visa and 3 others.
You're given an array where elements have colors, and you need to count adjacent pairs that share the same color. It sounds straightforward until you hit the live assessment and realize the naive pass through the array isn't the only trap. Visa, Roblox, Capital One, and Uber have all asked this. The acceptance rate hovers around 55%, which means half the people who attempt it walk away empty-handed. The trick isn't complex, but the edge cases will kill you if you're not careful. StealthCoder solves it instantly if you blank on the approach during your OA.
Companies that ask "Number of Adjacent Elements With the Same Color"
Number of Adjacent Elements With the Same Color 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 who got tired of watching his cohort grind for six months and still get filtered at the OA stage.
Get StealthCoderThe core pattern is simple: iterate through the array and count every adjacent pair where colors match. One pass, linear time. But candidates stumble on three things: off-by-one errors in the loop bounds, forgetting that a single match counts once not twice, and mishandling input validation. The obvious O(n) solution works, but you need to be precise about what 'adjacent' means and whether the problem expects you to count ordered pairs or unordered matches. Many people overcomplicate it by building a map or trying a two-pointer approach when a single forward scan is all you need. If you blank on the structure during the assessment, StealthCoder delivers a clean, working solution in seconds while the proctor sees nothing.
Pattern tags
You know the problem.
Make sure you actually pass it.
Number of Adjacent Elements With the Same Color 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 who got tired of watching his cohort grind for six months and still get filtered at the OA stage. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Number of Adjacent Elements With the Same Color interview FAQ
Is this problem really at medium difficulty?+
Yes. The acceptance rate of 55% confirms it's genuinely medium, not easy. Most people understand the concept but fail on implementation details like loop boundaries or handling edge cases. The conceptual overhead is low, but execution precision is required.
What's the time complexity I should aim for?+
O(n) is the only reasonable target. You must scan the array once. Any approach using nested loops or building auxiliary data structures is overengineered. A single pass is sufficient and necessary.
Will this problem appear in my Uber or Visa OA?+
Yes, all four of these companies are reported to ask it. Array problems of this difficulty are common gate-keeping questions. If you see it, a correct solution unlocks the next round. If you blank, you lose momentum.
What mistake do most people make?+
Off-by-one errors in loop bounds and double-counting matches. Some iterate to array.length instead of array.length - 1, causing index errors. Others count both (i, i+1) and (i+1, i) as separate matches when they should count once.
Is there a trick I should know before the assessment?+
No hidden trick. This is a straightforward pattern matching problem. The 'trick' is discipline: define exactly what you're counting, write clean loop bounds, and trace through a small example by hand before submitting. Most failures are careless, not conceptual.
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