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();

 

 

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代码如下：

 1 public class Solution {
 2     private int[] origal=null;
 3     // private List<Integer> list=new ArrayList<>();
 4     Random random=new Random();
 5     public Solution(int[] nums) {
 6         if(nums==null||nums.length==0) origal=nums;
 7         origal=nums.clone();
 8    
 9     }
10     
11     /** Resets the array to its original configuration and return it. */
12     public int[] reset() {
13         if(origal==null||origal.length==0) return origal;
14         return origal.clone();
15     }
16     
17     /** Returns a random shuffling of the array. */
18     public int[] shuffle() {
19         if(origal==null||origal.length==0) return origal;
20         
21         int[] res=new int[origal.length];
22         res=origal.clone();
23 
24         for(int i=res.length-1;i>0;i--)
25         {
26             try{
27             int p=random.nextInt(i+1);
28             int temp=res[p];
29             res[p]=res[i];
30             res[i]=temp;
31             }catch(ArrayIndexOutOfBoundsException e){}
32         }
33         return res;
34     }
35 }
36 
37 /**
38  * Your Solution object will be instantiated and called as such:
39  * Solution obj = new Solution(nums);
40  * int[] param_1 = obj.reset();
41  * int[] param_2 = obj.shuffle();
42  */