Balanced Brackets II

Difficulty: Medium · Topics: Stack, Parsing

Difficulty: Medium | Tags: Stack, Parsing

Description

Given a string representing Java source code, check if all brackets ({}, (), []) are properly matched and nested. Brackets inside string literals ("..."), character literals ('x'), line comments (//), and block comments (/* ... */) must be ignored.

Implement:

isBalanced(String sourceCode) → boolean

Return true if all brackets in the actual code (excluding strings, char literals, and comments) are properly matched.

Examples

Example 1 — Bracket inside string:

Input:  "String s = \"}\"; if (true) { }"
Output: true
Explanation: The } inside the string literal is ignored.

Example 2 — Bracket in comment:

Input:  "// { in comment\nint x = (1 + 2);"
Output: true
Explanation: The { in the line comment is ignored.

Example 3 — Unbalanced code:

Input:  "public void foo() { if (true) { }"
Output: false
Explanation: Missing one closing brace for the method body.

Example 4 — Char literal:

Input:  "char c = '{'; int[] arr = new int[5];"
Output: true
Explanation: The { inside the char literal is ignored.

Constraints

Brackets inside string literals, character literals, and comments must be ignored.
Handle escape sequences in strings and char literals (\", \', \\).
Source code length ≤ 10⁶.

Hints

Hint 1

Build a lexer that tracks whether you're inside a string, char literal, line comment, or block comment.

Hint 2

Only push/pop brackets when in "normal code" mode — not inside any literal or comment.

Practice this problem

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