Problem database last updated: June 20, 2025
4 problems · 0 Easy, 3 Medium, 1 Hard · Ranked #286 of 458
0 Easy
0% · avg 23%
3 Medium
75% · avg 59%
1 Hard
25% · avg 18%
Based on 4 reported problems, National Instruments interviews are slightly harder than average - 25% Hard vs 18% across all companies. The majority (75%) of questions are Medium difficulty, which is typical for companies that want to see solid fundamentals without excessive trick questions.
Compared to the industry average, National Instruments puts unusual emphasis on stack (50% of problems, 5.8x the industry average), dynamic-programming (50% of problems, 2.5x the industry average). If you're short on time, these are the categories to double down on.
The most common topics are stack (50%), dynamic-programming (50%), array (50%), string (25%). Problems below are sorted by frequency, the ones at the top are asked most often.
| Problem | Difficulty | Frequency | Topics | |
|---|---|---|---|---|
Decoded String at Index You are given an encoded string s. To decode the string to a tape, the encoded string is read one character at a time and the following steps are taken: | Medium | Very Likely | stringstack | Solve |
Champagne Tower We stack glasses in a pyramid, where the first row has 1 glass, the second row has 2 glasses, and so on until the 100th row. Each glass holds one cup of champag... | Medium | Very Likely | dynamic-programming | Solve |
Trapping Rain Water Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. | Hard | Likely | arraytwo-pointersdynamic-programming | Solve |
Snakes and Ladders You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. b... | Medium | Likely | arraybreadth-first-searchmatrix | Solve |
Decoded String at Index
SolveYou are given an encoded string s. To decode the string to a tape, the encoded string is read one character at a time and the following steps are taken:
Champagne Tower
SolveWe stack glasses in a pyramid, where the first row has 1 glass, the second row has 2 glasses, and so on until the 100th row. Each glass holds one cup of champag...
Trapping Rain Water
SolveGiven n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.
Snakes and Ladders
SolveYou are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. b...
Frequency scores are based on crowdsourced interview reports. A higher score means the problem has been reported more often in recent National Instruments interviews.
Very Likely
75-100%
Likely
50-74%
Sometimes
25-49%
Rare
0-24%
National Instruments interviews focus heavily on stack, dynamic-programming, array problems. If you're short on time, these are the categories to prioritize. The problems on this page are sorted by frequency, so start from the top and work your way down.
Beyond solving problems, practice explaining your approach. National Instruments interviewers care about your thought process - how you break down a problem, consider edge cases, and evaluate tradeoffs between solutions. A clean O(n) solution you can explain clearly beats an O(log n) solution you can't articulate.
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National Instruments has been reported to ask 4 distinct coding problems. The most common topics are stack, dynamic-programming, array. 0 are Easy difficulty, 3 are Medium, and 1 are Hard. Problems are sorted by frequency - the ones at the top are asked most often.
Based on 4 reported problems, National Instruments interviews are slightly harder than average - 25% Hard vs 18% across all companies. 75% of questions are Medium difficulty. Focus on the high-frequency Medium problems first, then work through the Hard ones.
Start with the highest-frequency problems listed on this page. Focus on the core topics: stack, dynamic-programming, array. Practice solving them under time pressure and explaining your approach out loud. Mock interviews with AI can simulate the real experience.
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