Monistus

var readline = require("readline");
const INPUT_LINES = 1;

// Super Epic Input Tool For Testing :))))
// Fun fact to the moderators: I'm a professional Node.js developer (I have done it as a job and a freelancer, since I was 13!).
// Kinda sad you use such old Node.js version as 12, but suit yourself.

if (process.env.TEST !== "1") {
  let lines = [];
  const r = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    terminal: false,
  });
  r.on("line", (line) => {
    lines.push(line);
    if (lines.length === INPUT_LINES) {
      run(...lines);
      r.close();
    }
  });
} else {
  // This part of the program is used for input management while testing the code :)
  // CSES doesn't run this, so it can be pretty much ignored. :)
  const lines = require("fs")
    .readFileSync(`${__filename.replace(".js", ".txt")}`)
    .toString()
    .split("\n");
  if (lines.length === INPUT_LINES) run(...lines);
  else {
    let temp = [];
    lines.forEach((val, index) => {
      temp.push(val);
      const NOT_FIRST_INDEX = INPUT_LINES === 1 || index != 0;
      if (NOT_FIRST_INDEX && (index + 1) % INPUT_LINES === 0) {
        run(...temp);
        temp = [];
      }
    });
  }
}

// SOLUTION STARTS
function run(input) {
  let chars = input.split("");
  let index = 0;
  while (index < chars.length) {
    const char = chars[index];
    const number = parseInt(char) + 1;
    if (isNaN(number)) {
      index++;
    } else {
      const spliced = chars.splice(index, number).join("");
      let temp = chars;
      temp.splice(
        index,
        0,
        `${spliced.slice(1, spliced.length)}${spliced.slice(1, spliced.length)}`
      );
      chars = temp.join("").split("");
    }
  }
  console.log(chars.join(""));
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 1, 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 1, 2

Verdict: ACCEPTED

Test 7

Group: 1, 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 11

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 12

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 13

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 2

Verdict: TIME LIMIT EXCEEDED