Medium
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.
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
Example 3:
Input: nums = [1], target = 0
Output: -1
Constraints:
1 <= nums.length <= 5000
-104 <= nums[i] <= 104
nums
are unique.nums
is an ascending array that is possibly rotated.-104 <= target <= 104
-spec search(Nums :: [integer()], Target :: integer()) -> integer().
search(Nums, Target) ->
search(Nums, Target, 0, length(Nums) - 1).
search(_, _, L, R) when L > R -> -1;
search(Nums, Target, L, R) ->
Mid = (L + R) div 2,
Val = lists:nth(Mid + 1, Nums),
Start = lists:nth(L + 1, Nums),
case Val of
Target -> Mid;
_ ->
if
(Val >= Start andalso Target >= Start andalso Target < Val)
orelse (Val < Start andalso (Target >= Start orelse Target < Val)) ->
search(Nums, Target, L, Mid - 1);
true ->
search(Nums, Target, Mid + 1, R)
end
end.