decompress

Question

given a compressed string as input, return a string that is decompressed.

input:

("2{q}3{tu}v") ("2{y3{o}}v")

Output:

qqtututuv yoooyooos

Solution

as seen from our input we can have nested compressed strings so we have to evaluate our strings carefully.

if we don't have any nesteed groups we could use a stack to remember the different gro

Javascript

const decompressBraces = (s) => {
  const stack = [];
  const numbers = "123456789";

  for (const char of s) {
    //console.log(stack)
    if (numbers.includes(char)) {
      stack.push(Number(char));
    } else {
      if (char === "}") {
        //pop routine
        let str = "";
        while (typeof stack[stack.length - 1] !== "number") {
          let popped = stack.pop();
          str = popped + str;
        }
        let num = stack.pop();
        let finStr = str.repeat(num);
        console.log(finStr);
        stack.push(finStr);
      } else if (char !== "{") {
        stack.push(char);
      }
    }
  }
  console.log(stack);
  return stack.join("");
};

Java

Concepts

Stacks

Patterns

• Stack