leetcode-38 外观数列

/**
 * @param {number} n
 * @return {string}
 */
var countAndSay = function (n) {
  function getNum(numStr) {
    let curStr = numStr[0];
    let count = 0;
    let result = "";
    for (let i = 0; i < numStr.length; ++i) {
      if (numStr[i] === curStr) {
        count++;
      } else {
        result += count + curStr;
        count = 1;
        curStr = numStr[i];
      }
      if (i === numStr.length - 1) {
        result += count + curStr;
      }
    }
    return result;
  }
  let num = "1";
  for (let i = 1; i < n; ++i) {
    num = getNum(num);
  }
  return num;
};
// countAndSay();