search-in-rotated-sorted-array.js

/**There is an integer array nums sorted in ascending order (with distinct values).

Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k < nums.length) such that the resulting array is [nums[k], nums[k+1], ..., nums[n-1], nums[0], nums[1], ..., nums[k-1]] (0-indexed). For example, [0,1,2,4,5,6,7] might be rotated at pivot index 3 and become [4,5,6,7,0,1,2].

Given the array nums after the possible rotation and an integer target, return the index of target if it is in nums, or -1 if it is not in nums.

You must write an algorithm with O(log n) runtime complexity. */
/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
 var search = function(nums, target) {
    let result = -1,
      low = 0,
      high = nums.length - 1,
      mid;
  
    while (low <= high) {
      mid = Math.floor((low + high) / 2);
  
      if (nums[mid] === target) {
        result = mid;
        break;
      }
  
      if (nums[low] <= nums[mid]) {
        if (target > nums[mid] || target < nums[low]) {
          low = mid + 1;
        } else {
          high = mid - 1;
        }
      } else {
        if (target < nums[mid] || target > nums[high]) {
          high = mid - 1;
        } else {
          low = mid + 1;
        }
      }
    }
  
    return result;
  };