题解 | 动态整数集最近值提取

import java.util.Scanner;
import java.util.TreeSet;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scanner=new Scanner(System.in);
		int q=scanner.nextInt();
		TreeSet<Integer> set=new TreeSet<>();
		for (int i = 0; i < q; i++) {
			int op=scanner.nextInt();
			int x=scanner.nextInt();
			if(op==1) {
				if(!set.add(x)) {
					System.out.println("Already Exist");
				}
			}else if(op==2) {
				if(set.isEmpty()) {
					System.out.println("Empty");
				}else {
					if(set.contains(x)) {
						set.remove(x);
						System.out.println(x);
					}else {
						Integer a1=set.lower(x);
						Integer a2=set.higher(x);
						if(a1==null||a2==null) {
							set.remove(a1==null?a2:a1);
							System.out.println(a1==null?a2:a1);
						}else {
							long d1=(long)x-a1;
							long d2=(long)a2-x;
							if(d1<=d2) {
								set.remove(a1);
								System.out.println(a1);
							}else {
								set.remove(a2);
								System.out.println(a2);
							}
						}
					}
					
					
				}
			}
		}

	}

}

这一题我后面一直是10个案例过9个，问了下Ai，原来是当前后距离相等时，要求返回值更小的，这一点我那个时候没有注意到