(33)Search in Rotated Sorted Array

 1 public class SearchRotatedSortedArray {
 2     public static int search(int[] A, int target) {
 3         int start = 0;
 4         int end = A.length - 1;
 5         int mid;
 6 
 7         while (start + 1 < end) {
 8             mid = start + (end - start) / 2;
 9             if (A[mid] == target) {
10                 return mid;
11             }
12             if (A[start] < A[mid]) {
13                 // situation 1, red line
14                 if (A[start] <= target && target <= A[mid]) {
15                     end = mid;
16                 } else {
17                     start = mid;
18                 }
19             } else {
20                 // situation 2, green line
21                 if (A[mid] <= target && target <= A[end]) {
22                     start = mid;
23                 } else {
24                     end = mid;
25                 }
26             }
27         } // while
28 
29         if (A[start] == target) {
30             return start;
31         }
32         if (A[end] == target) {
33             return end;
34         }
35         return -1;
36     }
37 
38     public static void main(String[] args) {
39         int[] a = {
40                 3,4, 5, 6, 7, 0, 1, 2
41         };
42         System.out.println(search(a, 1));
43     }
44 }