Least Operators to Express Number
A hard-tier problem at 48% community acceptance, tagged with Math, Dynamic Programming, Memoization. Reported in interviews at Snap and 0 others.
Least Operators to Express Number is a hard DP problem that shows up at Snap and tests whether you can think about expression building as a state-space search. The 48% acceptance rate tells you this isn't a pattern-match problem. Most candidates either brute-force permutations of operators (slow and wrong) or miss that memoization state needs to track both the current sum and remaining target. If this lands on your live assessment and you blank on the DP formulation, StealthCoder solves it invisibly while you stay in control.
Companies that ask "Least Operators to Express Number"
Least Operators to Express Number 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 FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoderThe core trick is recognizing that you're not just trying operators sequentially. You need to build expressions where each number can be preceded by +, -, *, or / (with precedence rules). The naive approach explores all combinations without pruning, which explodes. The real solution uses memoization to cache (current index, current result so far) states, then explores what the next operator choice yields. Most candidates get stuck because they treat it like a simple expression-evaluation problem instead of a path-finding problem where operators define transitions. The state-space is smaller than it looks, but you have to see it first. If you're grinding DP but haven't hit this exact pattern, StealthCoder handles the state definition and operator precedence logic during your OA.
Pattern tags
You know the problem.
Make sure you actually pass it.
Least Operators to Express Number 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 FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Least Operators to Express Number interview FAQ
Is Least Operators to Express Number still asked at top companies?+
Yes, Snap has reported it. At a 48% acceptance rate, it's clearly not an easy screen-out problem. It shows up infrequently compared to standard DP, but when it does, it's a hard-level assessment. If you see it, the company is testing strong DP intuition.
What's the biggest trap in this problem?+
Treating it as a simple recursion over operators without proper memoization. You'll time out. The second trap is incorrect state definition. Your memo key must capture both progress through numbers and the current accumulated value, not just position. Miss either, and your solution fails.
How does Math and Dynamic Programming relate here?+
Math handles operator precedence and expression semantics. DP is the search strategy. You're computing the minimum-cost path through a state space where each state is (position, current value) and edges are operator choices. Without both lenses, the problem looks impossible.
Can I solve this greedy, or is DP mandatory?+
DP is mandatory. Greedy fails because the globally optimal operator choice at step N can block you from a better overall expression later. You must explore multiple paths and memoize results to avoid re-exploring the same state.
How much time should I spend on this if I see it live?+
If you understand DP and memoization, 15-20 minutes to code. If you're seeing the pattern for the first time during the OA, it's easy to burn 40 minutes on a wrong approach. That's when the hedge matters most. StealthCoder gives you the state structure and operator loop immediately.
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