748. Largest Number At Least Twice of Others -- Python_python largest number at least twice of others-优快云博客

本文介绍了一种算法，用于确定数组中的最大元素是否至少是其他所有元素的两倍。如果是，则返回该元素的索引；否则返回-1。文章还讨论了列表的深拷贝和浅拷贝问题，并提供了一个具体的实现案例。

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748. Largest Number At Least Twice of Others

In a given integer array nums, there is always exactly one largest element.

Find whether the largest element in the array is at least twice as much as every other number in the array.

If it is, return the index of the largest element, otherwise return -1.

Example 1:

Input: nums = [3, 6, 1, 0]
Output: 1
Explanation: 6 is the largest integer, and for every other number in the array x,
6 is more than twice as big as x.  The index of value 6 is 1, so we return 1.

Example 2:

Input: nums = [1, 2, 3, 4]
Output: -1
Explanation: 4 isn't at least as big as twice the value of 3, so we return -1.

Note:

nums will have a length in the range [1, 50].
Every nums[i] will be an integer in the range [0, 99].

思路：

这个题目我思考的角度就是一个列表深拷贝和浅拷贝的问题。（Ps:近几次的提交中总是会忽略空列表或者只有一个列表的情况，以后需要注意哦）

代码：

class Solution:
    def dominantIndex(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        import copy
        L=copy.deepcopy(nums)
        L.sort()
        if len(L)<=1:
            return 0
        else:
            if L[-1]>=L[-2]*2:
                return nums.index(L[-1])
            else:
                return -1