/**
 * 折半插入排序【JavaScript版本】
 */
function binaryInsertSort(arr, len) {
  // 数组长度校验【非必须】
  len = arr.length === len
    ? len
    : arr.length

  // 遍历
  for (let i = 1; i < len; i++) {
    const temp = arr[i]
    let lowIndex = 0
    let highIndex = i - 1

    while (lowIndex <= highIndex) {
      // 注意：取整,javascript这里取整，会出现空指针
      const mid = Math.ceil((lowIndex + highIndex) / 2)

      if (arr[mid] <= temp) {
        // 右侧
        lowIndex = mid + 1
      } else {
        // 左侧
        highIndex = mid - 1
      }
    }
    // 元素后移
    for (let j = i - 1; j > highIndex; --j) {
      arr[j + 1] = arr[j]
    }
    arr[highIndex + 1] = temp
  }
  // 返回经过折半插入排序处理的有序数组
  return arr
}


// 测试用例
const dealArr = [5, 2, 7, 3, 18, 8, 12, 1]
console.log('插入排序前：', dealArr)
const sortResult = binaryInsertSort(dealArr, 7)
console.log('插入排序后：', sortResult)