ti0ma / balanced-brackets

Balanced brackets kata (problem and solution)

Balanced Brackets HackerRank

Problem

A bracket is considered to be any one of the following characters: (, ), {, }, [, or ].

Two brackets are considered to be a matched pair if the an opening bracket (i.e., (, [, or {) occurs to the left of a closing bracket (i.e., ), ], or }) of the exact same type. There are three types of matched pairs of brackets: [], {}, and ().

A matching pair of brackets is not balanced if the set of brackets it encloses are not matched. For example, {[(])} is not balanced because the contents in between { and } are not balanced. The pair of square brackets encloses a single, unbalanced opening bracket, (, and the pair of parentheses encloses a single, unbalanced closing square bracket, ].

By this logic, we say a sequence of brackets is considered to be balanced if the following conditions are met:

• It contains no unmatched brackets.

• The subset of brackets enclosed within the confines of a matched pair of brackets is also a matched pair of brackets.

Given strings of brackets, determine whether each sequence of brackets is balanced. If a string is balanced, return true; otherwise, return false.

Level 1

In this level, you will only need check the strings that have only one root element for each pair; you will not have more than two pairs inside the same pair (e.g. ({}[])).

Examples of strings you will recieve:

• Valid: {{}} and (([{[[{}]]}]))
• Not valid: {{[}} and (([{[[{)}]]}]))

Run npm run level1 to check this level

Level 2

In this level you will have any kind of bracket combination could be passed.

Examples of strings you will recieve:

• Valid: {{}[]} and (([{[[{}]][{}{[]}()]}]))
• Not valid: {{[}][]} and (([{[[{)}][{]({)}]}]))

Run npm run level2 to check this level

Level 3 (Bonus Track)

In this level, you will need to create a prepocessor to validate any javascript code's brackets parity and, as same as the previous levels, return true when the brackets are balanced and false otherwise. Note: The code provided in the level check will not have any comments.

Valid code:

(function test(valid) {
  if(valid) {
    return ((1 + 2) > (true || false));
  }
  return [1, 2, 3].filter((i) => {return (i > 1);});
})(true);

Not valid code:

(function test(valid) {
  if(valid) {
    return ((1 + 2)) > (true || false));
  return [1, 2, 3].filter((i) => {return (i > 1)];});
}){(true);

Run npm run level3 to check this level