Search in Rotated Sorted Array

二分题，先多写点判断再压缩状态就可以得到非常简短的代码了Ologn&O1

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int len = nums.size();
        int mid = len / 2;
        int midnum = nums[0];

        if(midnum == target) {
            return 0;
        }

        for(int l = 0, r = len; l<mid; mid = (l+r)/2) {
            if(nums[mid] == target) {
                return mid;
            }
            if( ((nums[mid] - target) 
                ^ (target - midnum) 
                ^ (nums[mid] - midnum)) < 0 ) {
                l = mid;
            } else {
                r = mid;
            }
        }
        return nums[mid] == target ? mid : -1;
    }
};