Snowflake Coding Interview Questions
100 Snowflake coding interview problems with full optimal solutions — 30 easy, 50 medium, 20 hard. Every problem ships with multiple approaches (brute-force first, then the optimal), complexity tables for each, company-specific tips on what an Snowflake interviewer values, and a FAQ section.
Showing 16 problems of 100
- #81hardsometimes asked
81. Median of Two Sorted Arrays
Find the median of two sorted arrays in O(log(min(m, n))). Snowflake asks this to test binary search on partitions — directly relevant to merging sorted micro-partitions for median computation during APPROX_PERCENTILE follow-up.
- #82hardsometimes asked
82. Regular Expression Matching
Implement regex matching with . and *. Snowflake asks this for 2D DP with branching transitions — directly relevant to their REGEXP_LIKE evaluator and LIKE pattern matching.
- #84hardsometimes asked
84. Reverse Nodes in k-Group
Reverse a linked list in groups of k nodes. Snowflake asks this because batched reversal in groups is precisely how their executor flips row direction in fixed-size batches for ORDER BY DESC over partial micro-partitions.
- #85hardrarely asked
85. Substring with Concatenation of All Words
Find all starting indices where a substring is a concatenation of every word exactly once. Snowflake asks this for multi-key sliding-window mastery — relevant to multi-column join-key matching in streaming joins.
- #86hardrarely asked
86. Longest Valid Parentheses
Find the longest valid parentheses substring. Snowflake asks this for stack-with-index — relevant to recovering nesting depth during SQL parser error reporting.
- #87hardrarely asked
87. Sudoku Solver
Solve a 9x9 Sudoku puzzle. Snowflake asks this to test backtracking with constraint propagation — relevant to constraint solving during type inference and constraint validation.
- #88hardsometimes asked
88. First Missing Positive
Find the smallest missing positive integer in O(n) time and O(1) space. Snowflake asks this for the cyclic-placement trick — relevant to building dense column-id mappings during data ingestion.
- #89hardsometimes asked
89. Trapping Rain Water
Compute the volume of water trapped between bars after rain. Snowflake asks this for the two-pointer trick — relevant to computing memory-bound estimation in their planner where left and right side constraints both matter.
- #92hardrarely asked
92. N-Queens
Place n queens on an n x n chessboard so none attack each other. Snowflake asks this as the canonical backtracking-with-constraint-bitmask — relevant to constraint solving during query rewrite where multiple non-conflicting predicates must be selected.
- #93hardrarely asked
93. N-Queens II
Count the number of distinct n-queens solutions. Snowflake asks this for pure constraint counting — directly relevant to counting valid plan configurations during planner exploration.
- #94hardsometimes asked
94. Insert Interval
Insert a new interval into a sorted list of non-overlapping intervals, merging where needed. Snowflake asks this for streaming-friendly interval management — relevant to incremental micro-partition coalescing during continuous ingestion.
- #95hardrarely asked
95. Valid Number
Determine whether a string is a valid number (integer, decimal, or scientific notation). Snowflake asks this because their SQL parser must tokenize numeric literals correctly — and the spec is full of edge cases.
- #96hardrarely asked
96. Text Justification
Justify text to a fixed width, distributing spaces evenly. Snowflake asks this to test careful greedy packing with edge-case spacing — relevant to formatted CSV unload and result-set pretty-printing.
- #97hardsometimes asked
97. Largest Rectangle in Histogram
Find the largest rectangle area in a histogram. Snowflake asks this for the monotonic-stack pattern — directly relevant to range-max queries during query optimization.
- #98hardrarely asked
98. Maximal Rectangle
Find the largest rectangle of 1s in a binary matrix. Snowflake asks this as the 2D extension of Largest-Rectangle-in-Histogram — relevant to range-max queries over rectangular data tiles.
- #99hardrarely asked
99. Scramble String
Determine whether one string can be obtained by recursively partitioning another. Snowflake asks this for recursive partitioning with memoization — same recursion shape as proving plan equivalence under reordering.