# Search in Rotated Sorted Array

#1

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```

#2

The below solution uses modified binary search forcing the lower or upper boundary based on the where the target could be. Below is the Go solution.

``````func search(nums []int, target int) int {
l, r := 0, len(nums)-1
for l<=r{
m := (l+r)/2
if nums[m] == target {
return m
}else if nums[l]<=nums[m]{
if target >= nums[l] && target < nums[m]{
r = m-1
} else {
l = m+1
}
} else {
if target>nums[m] && target<=nums[r]{
l = m+1
} else {
r = m-1
}
}
}

return -1
}
``````