748. Largest Number At Least Twice of Others -- Python

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