[33] 搜索旋转排序数组

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
var search = function (nums, target) {
  //凡是从有序数列中寻找目标值，第一个应该想到二分法
  if (nums.length == 0) return -1
  let l = 0;
  let r = nums.length - 1;
  while (l <= r) {
    const mid = Math.floor((l + r) / 2);
    if (nums[mid] === target) return mid;
    if (nums[mid] >= nums[l]) {
      if (target >= nums[l] && target <= nums[mid]) {
        r = mid - 1
      } else {
        l = mid + 1
      }
    } else {
      if (target <= nums[r] && target >= nums[mid]) {
        l = mid + 1
      } else {
        r = mid - 1
      }
    }
  }
  return -1
};