p153

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LeetCode p153 Find Minimum in Rotated Sorted Array 题解

1.题目：

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.

题意：

输入一个有序数组，它有可能会从某处折断反转，找出数组中最小的那个数。

2.解题思路:

采用二分。。考虑边界条件。TUT

3.代码

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public class Solution {
    public int findMin(int[] nums) {
        int ans = nums[0];
		int len = nums.length;
		int left = 0;
		int right = len;
		int mid;
		for (;;) {
			mid = (left + right) / 2;
			// System.out.println(mid);
			if (mid - 1 < 0 || mid > len - 1)
				break;
			if (left > right)
				break;
			if (nums[mid] < nums[mid - 1]) {
				ans = ans < nums[mid] ? ans : nums[mid];
				break;
			} else {
				if (nums[mid] > nums[0]) {
					left = mid + 1;
				} else {
					right = mid;
				}
			}

		}
		return ans;
    }
}

4.一些总结：