Leetcode no.33

33. Search in Rotated Sorted Array

Suppose a sorted array 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.

public class Solution {
public int search(int[] nums, int target) {
if (nums.length==0) return -1;
int start= 0, end= nums.length-1;
while (start <= end){
int center= (start+end)/2;
if (nums[center] == target) return center;
if (nums[center]>= nums[start]){
if (target < nums[center] && target>= nums[start])
end= center-1;
else start= center+1;
}
if (nums[center]<=nums[end]){
if (target > nums[center] && target<=nums[end])
start= center+1;
else end= center-1;
}
}
return -1;
}
}