Shuffle an Array

题目链接

Shuffle a set of numbers without duplicates.

Example:

// Init an array with set 1, 2, and 3.
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.
solution.shuffle();
// Resets the array back to its original configuration [1,2,3].
solution.reset();
// Returns the random shuffling of array [1,2,3].
solution.shuffle();

解题思路：

这道题的目的是通过shuffle函数来打乱一个数组，通过reset函数来还原已打乱的数组。
在python里的random模块提供了shuffle方法来打乱数组，注意这个是原地打乱。
下面的这种思路其实是投机取巧了，其实可以通过洗牌算法实现：参考如下链接：Fisher–Yates shuffle 洗牌算法

python3代码实现：

import random
class Solution:

    def __init__(self, nums):
        """
        :type nums: List[int]
        """
        self.nums = nums
        

    def reset(self):
        """
        Resets the array to its original configuration and return it.
        :rtype: List[int]
        """
        return self.nums

    def shuffle(self):
        """
        Returns a random shuffling of the array.
        :rtype: List[int]
        """
        nums_cp = self.nums[:]
        random.shuffle(nums_cp)
        return nums_cp
        


# Your Solution object will be instantiated and called as such:
# obj = Solution(nums)
# param_1 = obj.reset()
# param_2 = obj.shuffle()