LeetCode 153. Find Minimum in Rotated Sorted Array

153. Find Minimum in Rotated Sorted Array

Medium

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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

這道題沒什麼太多彎路，就二分法縷清楚就行，Accepted代碼如下：

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

這解法顯示超過100%的時間複雜度和87.5%的空間複雜度，看來還算優的