sequence_bracket.js

// '[]{}()' - allowed characters
// Assusming that only above characters are used. Write a code to validate the given pattern.

// '[{[()]}]' - valid
// '[{[()]}]{[{()}]}' - valid
// '[()[]]'
// '[{[()]]}]' - not valid
// '[}' - not valid
// '[{]}' - not valid
// '[]{}' - valid

let allowedOpenChar = '[{('.split();
let allowedClosedChar = ']})'.split();
function findvalidSeq(seq) {
    let seqArr = seq.split('');
    let startSeq = {};
    let endSeq = {};
    for (let i = 0; i < seqArr.length; i++){
        if(seqArr[i] == '[' || eqArr[i] == '{' || eqArr[i] == '(' ){
            startSeq[seqArr[i]] = startSeq[seqArr[i]]?startSeq[seqArr[i]]:[];
            startSeq[seqArr[i]].push(i);

        } else {
            endSeq[seqArr[i]] = endSeq[seqArr[i]]?endSeq[seqArr[i]]: [];
            endSeq[seqArr[i]].push(i);
        }

    }
}