Validate and parse a bracketed list stringCodingYou are given a string s made of lowercase letters, commas, and the parentheses ( and ). A run of letters is a word. Commas separate items. A pair of parentheses wraps a group of…
Last asked Aug 2026
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- +1Design layer document with undo, redo and batchesCodingYou are building the core of a design tool. A document holds layers. Each layer has a unique integer id and a set of string properties, such as color, shape or size. A layer does…Last asked Jul 2026
+1Evaluate nested add and sub expressionsCodingImplement evaluate(expression: str) - int, which evaluates a string written in a small function-call language. An expression is either: - an integer literal, possibly negative…Last asked Jun 2026
+3Key-value store with nested transaction rollbackCodingImplement an in-memory key-value store whose string keys map to string values. It supports transactions, and transactions can be nested. Implement the class KeyValueStore: -…Last asked May 2026- +1Remove parentheses from a plus/minus expressionCodingWrite a function simplify(expr: str) - str that removes every parenthesis from an expression and gives each term the sign it really has. Input. A valid expression made of: -…
Longest valid bracket substring with nesting ranksCodingGiven a string made only of the characters (, ), , , { and }, return the length of the longest contiguous substring that is valid. A string is valid when all of these hold: 1…