题目描述:

给出两个整数集合A、B，求出他们的交集、并集以及B在A中的余集。

代码:

package lanqiao;import java.math.BigInteger;
import java.util.*;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();ArrayList A = new ArrayList();ArrayList in = new ArrayList(); //交集ArrayList un = new ArrayList(); //并集ArrayList yu = new ArrayList(); //余集for(int i = 0;i < n; i ++){A.add(sc.nextInt());}un.addAll(A);yu.addAll(A);int m = sc.nextInt();for(int i = 0;i < m;i ++){int b = sc.nextInt();if(A.contains(b)){in.add(b);yu.remove(yu.indexOf(b));}else{un.add(b);}}Collections.sort(in);Collections.sort(un);Collections.sort(yu);for (int i = 0; i < in.size(); i++) {if(i!=in.size()-1)System.out.print(in.get(i)+" ");else System.out.println(in.get(in.size()-1));}if(in.size()==0) System.out.println();for (int i = 0; i < un.size(); i++) {if(i!=un.size()-1) System.out.print(un.get(i)+" ");else System.out.println(un.get(un.size()-1));}for (int i = 0; i < yu.size(); i++) {if(i!=yu.size()-1) System.out.print(yu.get(i)+" ");else System.out.println(yu.get(yu.size()-1));}if(yu.size()==0) System.out.println();}
}