384:打乱数组

src/main/java/leetcode/editor/cn/ShuffleAnArray.java

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+//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 
+// 
+//
+// 
+//
+// 示例： 
+//
+// 
+//输入
+//["Solution", "shuffle", "reset", "shuffle"]
+//[[[1, 2, 3]], [], [], []]
+//输出
+//[null, [3, 1, 2], [1, 2, 3], [1, 3, 2]]
+//
+//解释
+//Solution solution = new Solution([1, 2, 3]);
+//solution.shuffle();    // 打乱数组 [1,2,3] 并返回结果。任何 [1,2,3]的排列返回的概率应该相同。例如，返回 [3, 
+//1, 2]
+//solution.reset();      // 重设数组到它的初始状态 [1, 2, 3] 。返回 [1, 2, 3]
+//solution.shuffle();    // 随机返回数组 [1, 2, 3] 打乱后的结果。例如，返回 [1, 3, 2]
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 1 <= nums.length <= 200 
+// -10⁶ <= nums[i] <= 10⁶ 
+// nums 中的所有元素都是 唯一的 
+// 最多可以调用 5 * 10⁴ 次 reset 和 shuffle 
+// 
+// Related Topics 数组 数学 随机化 👍 152 👎 0
+
+package leetcode.editor.cn;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+//384:打乱数组
+class ShuffleAnArray {
+    public static void main(String[] args) {
+        //测试代码
+//        Solution solution = new ShuffleAnArray().new Solution();
+    }
+
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+    class Solution {
+        private int[] array;
+        private int[] original;
+
+        private Random rand = new Random();
+
+        private List<Integer> getArrayCopy() {
+            List<Integer> asList = new ArrayList<Integer>();
+            for (int i = 0; i < array.length; i++) {
+                asList.add(array[i]);
+            }
+            return asList;
+        }
+
+        public Solution(int[] nums) {
+            array = nums;
+            original = nums.clone();
+        }
+
+        public int[] reset() {
+            array = original;
+            original = original.clone();
+            return array;
+        }
+
+        public int[] shuffle() {
+            List<Integer> aux = getArrayCopy();
+
+            for (int i = 0; i < array.length; i++) {
+                int removeIdx = rand.nextInt(aux.size());
+                array[i] = aux.get(removeIdx);
+                aux.remove(removeIdx);
+            }
+
+            return array;
+        }
+    }
+
+/**
+ * Your Solution object will be instantiated and called as such:
+ * Solution obj = new Solution(nums);
+ * int[] param_1 = obj.reset();
+ * int[] param_2 = obj.shuffle();
+ */
+//leetcode submit region end(Prohibit modification and deletion)
+
+}