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.

solution

class Solution {
public:
int search(vector<int>& nums, int target) {
const int N = nums.size();

for( int left = 0, right = N -1; left <= right; ) {
int mid = (left + right) / 2;
if(nums[mid] == target) return mid;

//right is sorted
if( nums[right] > nums[mid]) {
if( target > nums[mid] && target <= nums[right]) {
left = mid + 1;
}
else {
right = mid - 1;
}
}
//left is sorted
else {
if(target < nums[mid] && target >= nums[left]) {
right = mid -1;
}
else {
left = mid + 1;
}
}
}
return -1;
}
};

考虑需全面

要考虑到左右两边都有可能是 sorted