Find Minimum in Rotated Sorted Array——LeetCode

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).

Find the minimum element.

You may assume no duplicate exists in the array.

题目大意:给定一个有序数组,是经过旋转过的,不知道在哪儿旋转的,求数组最小元素。

解题思路:直接遍历可以,太low。二分搜索吧,有序数组旋转有个特征,旋转后面的元素比旋转点前面的所有元素都小。

Talk is cheap>>

    public int findMin(int[] nums) {
        if (nums == null || nums.length == 0) {
            return 0;
        }
        int low = 0;
        int high = nums.length - 1;
        int mid = 0;
        while (low <= high) {
            mid = (low + high) >> 1;
            int left = mid > 0 ? mid - 1 : 0;
            int right = mid < nums.length - 1 ? mid + 1 : nums.length - 1;
            if (nums[mid] <= nums[left] && nums[mid] <= nums[right]) {
                break;
            }
            if (nums[mid] >= nums[high]) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return nums[mid];
    }

 

posted @ 2015-04-22 12:08  丶Blank  阅读(180)  评论(0编辑  收藏  举报