使用 Set 数据结构从未排序的数组中删除重复项

给定一个未排序的整数数组，在删除重复元素后打印该数组。我们需要根据它们的第一次出现来打印不同的数组元素。

例子：

Input: arr[] = { 1, 2, 5, 1, 7, 2, 4, 2}
Output: 1 2 5 7 4
Explanation: {1, 2} appear more than one time.

Input: arr[] = { 3, 3, 4, 1, 1}
Output: 3 4 1

方法：

• 拿一套
• 在 Set 中插入所有数组元素。 Set 不允许重复，并且像 LinkedHashSet 这样的集合保持插入顺序，因此它将删除重复项，并且元素将以插入时的相同顺序打印。
• 将形成的集合转换为数组。
• 打印 Set 的元素。

下面是上述方法的实现：

C++

// CPP program to remove duplicates
// from unsorted array
#include 
using namespace std;
 
// Function to remove duplicate from array
void removeDuplicates(int arr[], int n)
{
    unordered_set s;
 
    // adding elements to LinkedHashSet
    for (int i = 0; i < n; i++)
        s.insert(arr[i]);
 
    // Print the elements of LinkedHashSet
    cout << "[ ";
    for (auto x : s)
        cout << x << " ";
    cout << "]";
}
 
// Driver code
int main()
{
    int arr[] = { 1, 2, 5, 1, 7, 2, 4, 2 };
    int n = sizeof(arr) / sizeof(arr[0]);
   
    // Function call
    removeDuplicates(arr, n);
}
 
// This code is contributed
// by Surendra_Gangwar

Java

// Java program to remove duplicates
// from unsorted array
 
import java.util.*;
 
class GFG {
 
    // Function to remove duplicate from array
    public static void removeDuplicates(int[] arr)
    {
        LinkedHashSet set
            = new LinkedHashSet();
 
        // adding elements to LinkedHashSet
        for (int i = 0; i < arr.length; i++)
            set.add(arr[i]);
 
        // Print the elements of LinkedHashSet
        System.out.print(set);
    }
 
    // Driver code
    public static void main(String[] args)
    {
        int arr[] = { 1, 2, 5, 1, 7, 2, 4, 2 };
       
        // Function call
        removeDuplicates(arr);
    }
}

Python3

# Python3 program to remove duplicates
def removeDulipcates(arr):
   
    # convert the arr into set and then into list
    return list(set(arr))
 
 
# Driver Code
arr = [1, 2, 5, 1, 7, 2, 4, 2]
 
# Function call
print(removeDulipcates(arr))
 
# This code is contributed
# by Mohit Kumar

C#

// C# program to remove duplicates
// from unsorted array
using System;
using System.Collections.Generic;
 
class GFG
{
    // Function to remove duplicate from array
    public static void removeDuplicates(int[] arr)
    {
        HashSet set = new HashSet();
 
        // adding elements to LinkedHashSet
        for (int i = 0; i < arr.Length; i++)
            set.Add(arr[i]);
 
        // Print the elements of HashSet
        foreach(int item in set) Console.Write(item + ", ");
    }
 
    // Driver code
    public static void Main(String[] args)
    {
        int[] arr = { 1, 2, 5, 1, 7, 2, 4, 2 };
       
        // Function call
        removeDuplicates(arr);
    }
}
 
// This code is contributed by 29AjayKumar

Javascript

 
// Javascript program to remove duplicates
// from unsorted array
 
// Function to remove duplicate from array
function removeDuplicates(arr)
{
    let set = new Set();
     
    // Adding elements to LinkedHashSet
    for(let i = 0; i < arr.length; i++)
        set.add(arr[i]);
     
    // Print the elements of LinkedHashSet
    document.write("[" + Array.from(set).join(", ") + "]");
}
 
 // Driver code
let arr = [ 1, 2, 5, 1, 7, 2, 4, 2 ];
 
// Function call
removeDuplicates(arr);
 
// This code is contributed by patel2127
 

输出

[ 4 7 5 1 2 ]

时间复杂度：O(N)