81. 搜索旋转排序数组 II(二分)(LeetCode)

81. 搜索旋转排序数组 II
将相等的部分删除再二分

class Solution {
public:
    bool search(vector<int>& nums, int target) {
        int R = nums.size() - 1;
        while(R >= 0 && nums[R] == nums[0]) --R;
        if(R < 0) return nums[0] == target;

        //首先二分出分界点
        int l = 0, r = R;
        while(l < r){
            int mid = l + r + 1 >> 1;
            if(nums[mid] >= nums[0]) l = mid;
            else r = mid - 1;
        }
        
        if(nums[0] >= target) l++, r = R;
        else r = l, l = 0;
        //二分出答案
        while(l < r){
            int mid = l + r >> 1;
            if(nums[mid] >= target) r = mid;
            else l = mid + 1;
        }
        return target == nums[l];
    }
};