1. 081

search-in-rotated-sorted-array-ii

2. 算法

http://www.cnblogs.com/grandyang/p/4325840.html

• O(lgn)

二分查找

3. 代码

class Solution {

public:

    bool search(int A[], int n, int target) {

        if (n == 0) return false;

        int left = 0, right = n - 1;

        while (left <= right) {

            int mid = (left + right) / 2;

            if (A[mid] == target) return true;

            else if (A[mid] < A[right]) {

                if (A[mid] < target && A[right] >= target) left = mid + 1;

                else right = mid - 1;

            } else if (A[mid] > A[right]){

                if (A[left] <= target && A[mid] > target) right = mid - 1;

                else left = mid + 1;

            } else --right;

        }

        return false;

    }

};