# 4.1.9 桶排序

function bucketSort(arr, bucketSize) {
    if (arr.length === 0) {
      return arr;
    }
 
    var i;
    var minValue = arr[0];
    var maxValue = arr[0];
    for (i = 1; i < arr.length; i++) {
      if (arr[i] < minValue) {
          minValue = arr[i];                //输入数据的最小值
      } else if (arr[i] > maxValue) {
          maxValue = arr[i];                //输入数据的最大值
      }
    }
 
    //桶的初始化
    var DEFAULT_BUCKET_SIZE = 5;            //设置桶的默认数量为5
    bucketSize = bucketSize || DEFAULT_BUCKET_SIZE;
    var bucketCount = Math.floor((maxValue - minValue) / bucketSize) + 1;   
    var buckets = new Array(bucketCount);
    for (i = 0; i < buckets.length; i++) {
        buckets[i] = [];
    }
 
    //利用映射函数将数据分配到各个桶中
    for (i = 0; i < arr.length; i++) {
        buckets[Math.floor((arr[i] - minValue) / bucketSize)].push(arr[i]);
    }
 
    arr.length = 0;
    for (i = 0; i < buckets.length; i++) {
        insertionSort(buckets[i]);                      //对每个桶进行排序，这里使用了插入排序
        for (var j = 0; j < buckets[i].length; j++) {
            arr.push(buckets[i][j]);                      
        }
    }
 
    return arr;
}

Array.prototype.bucketSort = function(num) {
  function swap(arr, i, j) {
    const temp = arr[i]
    arr[i] = arr[j]
    arr[j] = temp
  }
  const max = Math.max(...this)
  const min = Math.min(...this)
  const buckets = []
  const bucketsSize = Math.floor((max - min) / num) + 1
  for(let i = 0; i < this.length; i++) {
    const index = ~~(this[i] / bucketsSize)
    !buckets[index] && (buckets[index] = [])
    buckets[index].push(this[i])
    let l = buckets[index].length
    while(l > 0) {
      buckets[index][l] < buckets[index][l - 1] && swap(buckets[index], l, l - 1)
      l--
    }
  }
  let wrapBuckets = []
  for(let i = 0; i < buckets.length; i++) {
    buckets[i] && (wrapBuckets = wrapBuckets.concat(buckets[i]))
  }
  return wrapBuckets
}
const arr = [11, 9, 6, 8, 1, 3, 5, 1, 1, 0, 100]
console.log(arr.bucketSort(10))