Lexicographically Smallest String After Applying Operations LeetCode solution in JavaScript

1
var findLexSmallestString = function (s, a, b) {
2
  const n = s.length;
3
  const visited = new Set();
4
  const queue = [];
5

6
  visited.add(s);
7
  queue.push(s);
8

9
  let minNum = s;
10

11
  while (queue.length > 0) {
12
    const currNum = queue.shift();
13

14
    if (currNum < minNum) minNum = currNum;
15

16
    const justRotate = rotate(currNum);
17
    const justAdd = add(currNum);
18

19
    if (!visited.has(justRotate)) {
20
      visited.add(justRotate);
21
      queue.push(justRotate);
22
    }
23

24
    if (!visited.has(justAdd)) {
25
      visited.add(justAdd);
26
      queue.push(justAdd);
27
    }
28
  }
29

30
  return minNum;
31

32
  function rotate(num) {
33
    let rotatedNum = "";
34
    const start = n - b;
35

36
    for (let i = 0; i < b; i++) {
37
      rotatedNum += num.charAt(start + i);
38
    }
39

40
    const restDigs = num.substring(0, n - b);
41
    rotatedNum += restDigs;
42

43
    return rotatedNum;
44
  }
45

46
  function add(num) {
47
    let nextNum = "";
48

49
    for (let i = 0; i < n; i++) {
50
      let currDig = num.charAt(i);
51

52
      if (i % 2 == 0) {
53
        nextNum += currDig;
54
      } else {
55
        let newDig = (parseInt(currDig) + a) % 10;
56
        nextNum += newDig;
57
      }
58
    }
59

60
    return nextNum;
61
  }
62
};