#3461 - Check If Digits Are Equal in String After Operations I

Easy • View on LeetCode • View on GitHub

Problem Description

You are given a string s consisting of digits. Perform the following operation repeatedly until the string has exactly two digits:

For each pair of consecutive digits in s, starting from the first digit, calculate a new digit as the sum of the two digits modulo 10.
Replace s with the sequence of newly calculated digits, maintaining the order in which they are computed.

Return true if the final two digits in s are the same; otherwise, return false.

Solution

/**
 * @param {string} s
 * @return {boolean}
 */
var hasSameDigits = function(s) {
  while (s.length > 2) {
    let next = '';
    for (let i = 0; i < s.length - 1; i++) {
      next += (parseInt(s[i]) + parseInt(s[i + 1])) % 10;
    }
    s = next;
  }
  return s[0] === s[1];
};