- 描述
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 static int search(int[] arr, int key) {
if(arr == null || arr.length == 0)
return -1;
int low = 0, high = arr.length;
while(low != high) {
int mid = low + (high - low) / 2;
if(arr[mid] == key)
return mid;
if(arr[low] <= arr[mid]) {
if(key >= low && key < arr[mid]) {
high = mid;
}
else {
low = mid + 1;
}
}
else {
if(key > arr[mid] && key <= arr[high-1] ) {
low = mid + 1;
}
else {
high = mid;
}
}
}
return -1;
}
}
