2938.js

/** ------------------------------------------------------------------------------
 * 
 * 2938. Separate Black and White Balls
 * Topics: Two Pointer
 * https://leetcode.com/problems/separate-black-and-white-balls/?envType=daily-question&envId=2024-10-15
 * 
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @return {number}
 */
var minimumSteps = function (s) {
  let swaps = 0
  let zeroCounter = 0

  for (let i = s.length; i >= 0; i--) {
    if (s[i] === "0") zeroCounter++
    else swaps += zeroCounter
  }
  return swaps
}

console.log(minimumSteps("101"))