add: leetcode 0384 readme

leetcode/0384.Shuffle-an-Array/README.md

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+# [384.Shuffle an Array](https://leetcode-cn.com/problems/shuffle-an-array/)
+
+## 题目
+
+Given an integer array nums, design an algorithm to randomly shuffle the array. All permutations of the array should be equally likely as a result of the shuffling.
+
+Implement the Solution class:
+
+- Solution(int[] nums) Initializes the object with the integer array nums.
+- int[] reset() Resets the array to its original configuration and returns it.
+- int[] shuffle() Returns a random shuffling of the array.
+
+**Example 1**:
+
+    Input
+    ["Solution", "shuffle", "reset", "shuffle"]
+    [[[1, 2, 3]], [], [], []]
+    Output
+    [null, [3, 1, 2], [1, 2, 3], [1, 3, 2]]
+
+    Explanation
+    Solution solution = new Solution([1, 2, 3]);
+    solution.shuffle();    // Shuffle the array [1,2,3] and return its result.
+    // Any permutation of [1,2,3] must be equally likely to be returned.
+    // Example: return [3, 1, 2]
+    solution.reset();      // Resets the array back to its original configuration [1,2,3]. Return [1, 2, 3]
+    solution.shuffle();    // Returns the random shuffling of array [1,2,3]. Example: return [1, 3, 2]
+
+**Constraints:**
+
+- 1 <= nums.length <= 200
+- -1000000 <= nums[i] <= 1000000
+- All the elements of nums are unique.
+- At most 5 * 10000 calls in total will be made to reset and shuffle.
+
+## 题目大意
+
+给你一个整数数组 nums ，设计算法来打乱一个没有重复元素的数组。
+
+实现 Solution class:
+
+- Solution(int[] nums) 使用整数数组 nums 初始化对象
+- int[] reset() 重设数组到它的初始状态并返回
+- int[] shuffle() 返回数组随机打乱后的结果
+
+## 解题思路
+
+- 使用rand.Shuffle进行数组随机打乱
+
+## 代码
+
+```go
+package leetcode
+
+import "math/rand"
+
+type Solution struct {
+	nums []int
+}
+
+func Constructor(nums []int) Solution {
+	return Solution{
+		nums: nums,
+	}
+}
+
+/** Resets the array to its original configuration and return it. */
+func (this *Solution) Reset() []int {
+	return this.nums
+}
+
+/** Returns a random shuffling of the array. */
+func (this *Solution) Shuffle() []int {
+	arr := make([]int, len(this.nums))
+	copy(arr, this.nums)
+	rand.Shuffle(len(arr), func(i, j int) {
+		arr[i], arr[j] = arr[j], arr[i]
+	})
+	return arr
+}
+```