Allowed R6 · Within policy
{
"slug": "balanced-brackets",
"title": "Balanced Brackets",
"difficulty": "easy",
"tags": [
"coding",
"oa",
"swe",
"intern"
],
"is_free": true,
"locked": false,
"frequency": 0.6,
"last_reported_at": "2026-07-10T14:54:11.011428Z",
"url": "https://www.mokabla.com/en/c/dell/balanced-brackets",
"agent": {
"page": "https://www.mokabla.com/agent/en/c/dell/balanced-brackets",
"question": "https://www.mokabla.com/agent/_call/get_question?company=dell&question=balanced-brackets"
},
"company": {
"slug": "dell",
"name_en": "Dell Technologies Egypt"
},
"body_md": "## Problem\nOur configuration loader accepts expressions containing three kinds of brackets: `()`, `[]` and `{}`. Write a function that returns `true` if every opening bracket is closed by the matching kind in the correct order, and `false` otherwise. Any other characters in the string should be ignored. An empty string is balanced.\n\nThis is the warm-up on the Dell Egypt online assessment; the graders check the tricky orderings, not just the happy path.\n\n## Examples\n**Example 1**\nInput: `\"{ if (x[0]) { y = [1, 2]; } }\"`\nOutput: `true`, every bracket closes in LIFO order.\n\n**Example 2**\nInput: `\"([)]\"`\nOutput: `false`, `)` arrives while `[` is still the most recent open bracket.\n\n**Example 3**\nInput: `\"((\"`\nOutput: `false`, unclosed brackets at the end are not balanced.\n\n## Constraints\n- 0 ≤ length ≤ 10^5\n- Must be O(n) time; O(n) auxiliary space is acceptable\n- Do not use regular expressions that repeatedly strip pairs, that is O(n²)\n\n## What they look for\nA stack, a map from closers to openers, the early exit on a mismatch, and remembering to check the stack is empty at the end. Bonus if you say how you would return the index of the first offending bracket.",
"follow_ups_md": "- Return the index of the first unbalanced bracket instead of a boolean.\n- What is the minimum number of insertions to make the string balanced?",
"access": "Question bodies are paid content: a person buys 30 days of access per company (200 EGP or 200 points) in the human app. Agents get titles, tags and difficulty; bodies only for free questions."
}