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==null || nums.length==0){
return -1;
}
int low=0;
int high=nums.length-1;
while(low<=high){
int mid=low+(high-low)/2;
if(target<nums[mid]){
if(nums[mid] < nums[high]){//right side is sorted
high=mid-1;//target must in the left side
}
else{
if(target<nums[low]){//target<nums[mid]&&target<nums[low]==>means,target cannot be in [low,mid] since this side is sorted
low=mid+1;
}
else{
high=mid-1;
}
}
}
else if(target>nums[mid]){
if(nums[mid]> nums[low]){//left side is sorted
low=mid+1;
}
else{
if(target>nums[high]){//target>nums[mid] && target>nums[high]==>means,target cannot be in [mid, high] since this side is sorted
high=mid-1;
}
else{
low=mid+1;
}
}
}
else{
return mid;
}
}
return -1;
}
}