Added for 17 Jan

GeeksForGeeks/17-1-24/GFG.java

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+//{ Driver Code Starts
+//Initial Template for JAVA
+
+import java.io.*;
+import java.util.*;
+
+class GFG {
+    public static void main(String args[]) throws IOException {
+        BufferedReader read =
+            new BufferedReader(new InputStreamReader(System.in));
+        int t = Integer.parseInt(read.readLine());
+        while (t-- > 0) {
+            int n = Integer.parseInt(read.readLine());
+
+            String S[] = read.readLine().split(" ");
+
+            ArrayList<Integer> arr = new ArrayList<>();
+
+            for(int i=0; i<n; i++)
+                arr.add(Integer.parseInt(S[i]));
+
+            Solution ob = new Solution();
+            ArrayList<ArrayList<Integer>> res = ob.uniquePerms(arr,n);
+            for(int i=0; i<res.size(); i++)
+            {
+                for(int j=0; j<n; j++)
+                {
+                    System.out.print(res.get(i).get(j) + " ");
+                }
+                System.out.println();
+            }
+        }
+    }
+}
+// } Driver Code Ends
+
+
+//User function Template for Java
+
+class Solution 
+{
+    static Set<ArrayList<Integer>> ans;
+
+    static void helper(int idx, ArrayList<Integer> arr) 
+    {
+        int n = arr.size();
+        if (idx >= n) 
+        {
+            ArrayList<Integer> temp = new ArrayList<>(arr);
+            ans.add(temp);
+            return;
+        }
+
+        for (int i = idx; i < n; i++) 
+        {
+            Collections.swap(arr, i, idx);
+            helper(idx + 1, arr);
+            Collections.swap(arr, i, idx);
+        }
+    }
+
+    static ArrayList<ArrayList<Integer>> uniquePerms(ArrayList<Integer> arr, int n) 
+    {
+        ans = new HashSet<>();
+        Collections.sort(arr);
+        helper(0, arr);
+
+        ArrayList<ArrayList<Integer>> result = new ArrayList<>(ans);
+
+        Collections.sort(result, (a, b) -> {
+            for (int i = 0; i < n; i++) 
+            {
+                if (!a.get(i).equals(b.get(i))) 
+                {
+                    return a.get(i) - b.get(i);
+                }
+            }
+            return 0;       });
+
+        return result;
+    }
+}

GeeksForGeeks/17-1-24/README.md

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+Time complexity - O(n * n!)
+Space complexity - O(n * n!)

LeetCode/17-1-24/README.md

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+Time complexity - O(n)
+Space complexity - O(n)

LeetCode/17-1-24/Solution.java

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+class Solution 
+{
+    public boolean uniqueOccurrences(int[] arr) 
+    {
+        Map<Integer, Integer> count = new HashMap<>();
+        Set<Integer> occurrences = new HashSet<>();
+
+        for (final int a : arr)
+            count.merge(a, 1, Integer::sum);
+
+        for (final int value : count.values())
+            if (!occurrences.add(value))
+                return false;
+
+        return true;
+    }
+}