[leetcode]Search in Rotated Sorted Array @ Python

原题地址:https://oj.leetcode.com/problems/search-in-rotated-sorted-array/

题意:

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.

解题思路:二分查找的变种。

代码:

class Solution:
    # @param A, a list of integers
    # @param target, an integer to be searched
    # @return an integer
    def search(self, A, target):
        left = 0; right = len(A) - 1
        while left <= right:
            mid = (left + right) / 2
            if target == A[mid]:
                return mid
            if A[mid] >= A[left]:
                if target < A[mid] and target >= A[left]:
                    right = mid - 1
                else:
                    left = mid + 1
            elif A[mid] < A[right]:
                if target > A[mid] and target <= A[right]:
                    left = mid + 1
                else:
                    right = mid - 1
        return -1

 

posted @ 2014-06-09 10:52  南郭子綦  阅读(3551)  评论(0编辑  收藏