Valid Braces - CodeWars Challenge

You can use array to keep track of previously appeared opening braces and once any closing tag appears you need to match it with the last value of array if it's matching pop the last value out of else else return false, in the end if you're left with empty array return true else return false

function validBraces(braces){
  let tracer = []
  for(let i=0;i < braces.length; i++){
    if ( braces[i] === "(" || braces[i] === "{" || braces[i] === "["){
      tracer.push(braces[i])
    } else{
      if(tracer.length === 0) return false
      let lastValue = tracer[tracer.length-1]
      if( (braces[i] === ']' && lastValue === '[') || (braces[i] === '}' && lastValue === '{') || (braces[i] === ')' && lastValue === '('))
      {
        tracer.pop()
      } else {
        break;
      }
    }
  }
  return tracer.length === 0
}


console.log(validBraces( "()" )) // true
console.log(validBraces( "[]" )) // true
console.log(validBraces( "{}" )) // true
console.log(validBraces( "(){}[]" )) // true
console.log(validBraces( "([{}])" )) // true
console.log(validBraces( "(}" )) // false
console.log(validBraces( "[(])" )) // false
console.log(validBraces( "({})[({})]" )) // true
console.log(validBraces( "(})" )) // false
console.log(validBraces( "(({{[[]]}}))" )) //true
console.log(validBraces( "{}({})[]" )) // true
console.log(validBraces( ")(}{][" )) // false
console.log(validBraces( "())({}}{()][][" )) // false
console.log(validBraces( "(((({{" ))  // false
console.log(validBraces( "}}]]))}])" )) // false


You don't really need to use arrays here, you can just use regex and recursion:

const regex = /\(\)|\[\]|\{\}/;
const validBraces = braces => regex.test(braces)
  ? validBraces(braces.replace(regex, ''))
  : '' === braces

console.log(validBraces('{{}}')) // true
console.log(validBraces('{{[]}}')) // true
console.log(validBraces('{[{}]}')) // true
console.log(validBraces('({{}})')) // true
console.log(validBraces('{[()]}')) // true
console.log(validBraces('{{}[}')) // false
console.log(validBraces('{{]}}')) // false
console.log(validBraces('{}}')) // false
console.log(validBraces('{({}}')) // false
console.log(validBraces('((}}')) // false
console.log(validBraces('}[)}')) // false


function validBraces(braces){
 while(/\(\)|\[\]|\{\}/g.test(braces)){braces = braces.replace(/\(\)|\[\]|\{\}/g,"")}
 return !braces.length;
}

// double regex

Tags:

Javascript

String

Curly Braces

Braces

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