C :

#include <stdio.h>
#define LEN 2500

int n,m;
long long arr[LEN][2] = {0};/*0->存储数据,1->存储加点*/

void sort_q(int x,int y,long long tmp[LEN][2])
{
    int i = x , j = y;
    long long k[2];
    k[0] = tmp[x][0];
    k[1] = tmp[x][1];
    if (i < j)
    {
        while (i < j)
        {
            while (i < j && k[0] < tmp[j][0])
                j --;
            if (i < j)
            {
                tmp[i][0] = tmp[j][0];
                tmp[i][1] = tmp[j][1];
                i ++;
            }
            while (i < j && k[0] > tmp[i][0])
                i ++;
            if (i < j)
            {
                tmp[j][0] = tmp[i][0];
                tmp[j][1] = tmp[i][1];
                j --;
            }
        }
        tmp[i][0] = k[0];
        tmp[i][1] = k[1];
        sort_q(x,i-1,tmp);
        sort_q(i+1,y,tmp);
    }
    return ;
}

void init(void)
{
    int flag;
    int i,j;
    long long k;

    scanf("%d",&n);
    for (i = 1 ; i <= n ; i ++)
    {
        scanf("%lld",&k);
        arr[i][0] = k;
        arr[i][1] += 1;
    }

    scanf("%d",&m);
    for (i = n+1 ; i <= n+m ; i ++)
    {
        scanf("%lld",&k);
        flag = 1;
        for (j = 1 ; j <= n ; j ++)
        {
            if (arr[j][0] == k)
            {
                arr[j][1] += 2;
                flag = 0;
                break;
            }
        }
        if (flag)
        {
            arr[i][0] = k;
            arr[i][1] += 2;
        }
    }
    sort_q(1,i,arr);    /*快排*/
    return ;
}

void print()
{
    int i;
    for (i = 1 ; i <= LEN ; i ++)
    {
        if (arr[i][1] >= 3)
        {
            printf("%lld ",arr[i][0]);/*输出AB交集*/
        }
    }
    printf("\n");

    for (i = 1 ; i <= LEN ; i ++)
    {
        if (arr[i][1] != 0)
        {
            printf("%lld ",arr[i][0]);/*输出AB并集*/
        }
    }
    printf("\n");

    for (i = 1 ; i <= LEN ; i ++)
    {
        if (arr[i][1] == 1)
        {
            printf("%lld ",arr[i][0]);/*输出B在A中的余集*/
        }
    }

    return ;
}

int main(void)
{
    init();
    print();
    return 0;
}

C++ :

#include <stdio.h>
#include <stdlib.h>
 
int cmp(const void *a, const void *b)
{
    return *(int *)a - *(int *)b;
}
 
void intersection_set(int *a, int size_a, int *b, int size_b)
{
    int i = 0, j = 0;
    while (i < size_a && j < size_b)
    {
        if (a[i] == b[j])
        {
            printf("%d ", a[i]);
            ++i;
            ++j;
        }
        else if (a[i] < b[j])
            ++i;
        else
            ++j;
    }
    printf("\n");
}
 
void union_set(int *a, int size_a, int *b, int size_b)
{
    int i = 0, j = 0;
    while (i < size_a && j < size_b)
    {
        if (a[i] == b[j])
        {
            printf("%d ", a[i]);
            ++i;
            ++j;
        }
        else if (a[i] < b[j])
        {
            printf("%d ", a[i]);
            ++i;
        }
        else
        {
            printf("%d ", b[j]);
            ++j;
        }
    }
    while (i < size_a)
    {
        printf("%d ", a[i]);
        ++i;
    }
    while (j < size_b)
    {
        printf("%d ", b[j]);
        ++j;
    }
    printf("\n");
}
 
void difference_set(int *a, int size_a, int *b, int size_b)
{
    int i = 0, j = 0;
    while (i < size_a && j < size_b)
    {
        if (a[i] == b[j])
        {
            ++i;
            ++j;
        }
        else if (a[i] < b[j])
        {
            printf("%d ", a[i]);
            ++i;
        }
        else
            ++j;
    }
    while (i < size_a)
    {
        printf("%d ", a[i]);
        ++i;
    }
}
 
int main()
{
    int n, m;
    int a[1002] = { 0 }, b[1002] = { 0 };
 
    scanf("%d", &n);
    for (int i = 0; i < n; ++i)
        scanf("%d", &a[i]);
    scanf("%d", &m);
    for (int i = 0; i < m; ++i)
        scanf("%d", &b[i]);
 
    qsort(a, n, sizeof(int), cmp);
    qsort(b, m, sizeof(int), cmp);
 
    intersection_set(a, n, b, m);
    union_set(a, n, b, m);
    difference_set(a, n, b, m);
 
    return 0;
}

Python :

"""
@Author:Lixiang

@Blog(个人博客地址): https://lixiang007.top/

@WeChat：18845312866

"""
import math
import string
import sys
n=int(input())
a=list(map(int,input().strip().split(" ")))
m=int(input())
b=list(map(int,input().strip().split(" ")))
jiaoji=[]
bingji=[]
yuji=[]
for i in a:
    if i in b:
        jiaoji.append(i)
jiaoji=list(set(jiaoji))
jiaoji.sort()
for i in jiaoji:
    print(i,end=" ")
print("")
a1=a[:]
b1=b[:]
a1.extend(b1)
a1=list(set(a1))
a1.sort()
for i in a1:
    print(i,end=" ")
print("")
for i in a:
    if i not in b:
        yuji.append(i)
yuji.sort()
for i in yuji:
    print(i,end=" ")