# 盛大无线面试题

题目（盛大无线面试题）：在一个字符串数组中有红、黄、蓝三种颜色的球，且个数不相等、顺序不一致，请为该数组排序。使得排序后数组中球的顺序为:黄、红、蓝。例如：红蓝蓝黄红黄蓝红红黄红，排序后为：黄黄黄红红红红红蓝蓝蓝。

const ball = ['红', '蓝', '蓝', '黄', '红', '黄', '蓝', '红', '红', '黄', '红'];

function ballSort(ball, rule) {
  if (!ball.length) return [];
  if (!rule || !rule.length) return ball;
  let group = {};
  for (let i = 0; i < ball.length; i++) {

    // eslint-disable-next-line no-prototype-builtins
    if (group.hasOwnProperty(ball[i])) {
      group[ball[i]].push(ball[i]);
    } else {
      group[ball[i]] = [ball[i]];
    }
  }
  let newBall = [];
  for (let ii = 0; ii < rule.length; ii++) {
    newBall = newBall.concat(group[rule[ii]]);
  }
  group = null;
  return newBall;
}

console.time('ballSort');
console.log(ballSort(ball, ['黄', '红', '蓝']));
console.timeEnd('ballSort');