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033 Search In Rotated Sorted Array

/**
 * 
 * Ashish Patel
 * e: ashishsushilPatel@gmail.com
 * w: https://ashish.me
 *
 */

/* 
 * Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.
 * 
 * (i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]).
 * 
 * You are given a target value to search. If found in the array return its index, otherwise return -1.
 * 
 * You may assume no duplicate exists in the array.
 * 
 * Your algorithm's runtime complexity must be in the order of O(log n).
 * 
 * Example 1:
 * 
 * Input: nums = [4,5,6,7,0,1,2], target = 0
 * Output: 4
 * Example 2:
 * 
 * Input: nums = [4,5,6,7,0,1,2], target = 3
 * Output: -1
*/


function searchInRotatedSortedArray(nums, target) {
  let left = 0;
  let right = nums.length - 1;
  while (left <= right) {
    let mid = Math.floor((left + right) / 2)
    if (nums[mid] === target) {
      return mid
    }
    if(nums[left] <= nums[mid]){
      if(target >= nums[left] && target <= nums[mid]){
        right = mid - 1
      } else {
        left = mid + 1
      }
    } else {
      if(target <= nums[right] && target >= nums[mid]){
        left = mid + 1
      } else {
        right = mid - 1
      }
    }
  }
  return -1
}

test('search In Rotated Sorted Array', () => {
  expect(searchInRotatedSortedArray([4, 5, 6, 7, 0, 1, 2], 0)).toEqual(4)
  expect(searchInRotatedSortedArray([5, 6, 7, 0, 1, 2, 3], 2)).toEqual(5)
  expect(searchInRotatedSortedArray([4, 5, 6, 7, 0, 1, 2], 6)).toEqual(2)
});

Created 2020-03-03T19:02:59+00:00, updated 2020-03-05T06:34:48+00:00 · History · Edit