LeetCode：Search in Rotated Sorted Array

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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.

// https://leetcode.com/problems/search-in-rotated-sorted-array/
// Author : Chao Zeng
// Date   : 2015-3-31
class Solution {
public:
    int search(int A[], int n, int target) {
        int left = 0, right = n - 1;
        while (left <= right){
            int mid = (left + right)/2;
            if (A[mid] == target)
                return mid;
            if (A[right] > A[left]){//判断已排序数组是升序还是降序
                if (target < A[mid])
                    right = mid - 1;
                else if (target > A[mid])
                    left = mid + 1;
                else
                    return mid;
            }
            else{
                if (A[left] < A[mid])
                {
                    if (target <= A[mid] && target >= A[left])//注意=号
                        right = mid - 1;
                    else
                        left = mid + 1;
                }
                else if (A[left] > A[mid])
                {
                    if (target >= A[left] || target <= A[mid])
                        right = mid - 1;
                    else
                        left = mid + 1;
                }
                else{
                    if (A[left] == target)
                        return left;
                    else
                        left++;
                }
            }
        }
        return -1;
    }
};

LeetCode：Search in Rotated Sorted Array

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原文地址：http://blog.csdn.net/hnuzengchao/article/details/44775519