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
public int search(int[] nums, int target) {
int start = 0;
int end = nums.length-1;
while(start <= end){
int mid = (start+end)/2;
if(nums[mid] == target)
return mid;
else if( nums[mid] >= nums[start]){ // sorted on the left
if(nums[start] <= target && nums[mid] >= target){ // target exist in this sorted part
end = mid-1;
}else{ // target does not exist in sorted part, ignore sorted part
start = mid+1;
}
}else{
if(nums[mid] <= target && nums[end]>=target){ // target exist in right sorted part
start = mid+1;
}else{ // target does not exist in sorted part right
end = mid - 1;
}
}
}
return -1;
}