LeetCode 153. Find Minimum in Rotated Sorted Array

153. Find Minimum in Rotated Sorted Array

Difficulty:: Medium

Suppose an array sorted in ascending order 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.

Example 1:

Input: [3,4,5,1,2] 
Output: 1

Example 2:

Input: [4,5,6,7,0,1,2]
Output: 0

Solution

Language: Java

class Solution {
    public int findMin(int[] nums) {
        if (nums == null || nums.length == 0) {
            return -1;
        }
        int start = 0, end = nums.length - 1;
        int last = end;
        while (start + 1 < end) {
            int mid = start + (end - start) / 2;
            if (nums[mid] <= nums[last]) {
                end = mid;
            } else {
                start = mid;
            }
        }
        return Math.min(nums[end], nums[start]);
    }
}