add solution of problem 33: search in rotated sorted array

Author: ppulse

SearchInRotatedSortedArray33/README.md

@@ -0,0 +1,7 @@
+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.

SearchInRotatedSortedArray33/Solution.java

@@ -0,0 +1,53 @@
+public class Solution {
+    public int search(int[] nums, int target) {
+        if (nums == null || nums.length == 0)
+            return -1;
+        
+        int left = 0;
+        int right = nums.length - 1;
+        
+        while (left <= right) {
+            int mid = (left + right) >> 1;
+            
+            if (nums[left] < nums[right]) {
+                if (nums[mid] < target) {
+                    left = mid + 1;
+                } else if (nums[mid] > target) {
+                    right = mid - 1;
+                } else {
+                    return mid;
+                }
+            } else {
+                if (nums[mid] < target) {
+                    if (nums[mid] < nums[left]) {
+                        if (nums[left] < target) {
+                            right = mid - 1;
+                        } else if (nums[left] > target) {
+                            left = mid + 1;
+                        } else {
+                            return left;
+                        }
+                    } else {
+                        left = mid + 1;
+                    }
+                } else if (nums[mid] > target) {
+                    if (nums[mid] < nums[left]) {
+                        right = mid - 1;
+                    } else {
+                        if (nums[left] < target) {
+                            right = mid - 1;
+                        } else if (nums[left] > target) {
+                            left = mid + 1;
+                        } else {
+                            return left;
+                        }
+                    }
+                } else {
+                    return mid;
+                }
+            }
+        }
+        
+        return -1;
+    }
+}