题解 | 数组取精

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class Main {
    static class Element {
        int a; // 对应数组A的元素值
        int b; // 对应数组B的元素值
        int index;// 该元素在原数组中的索引（从1开始）

        // 构造方法：初始化a、b、index
        Element(int a, int b, int index) {
            this.a = a;
            this.b = b;
            this.index = index;
        }
    }

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int n = Integer.parseInt(br.readLine());

        String[] strA = br.readLine().split(" ");
        String[] strB = br.readLine().split(" ");

        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));

        List<Element> elements = new ArrayList<>();

        long sumA = 0, sumB = 0;

        for (int i = 0; i < n; i++) {
            int a = Integer.parseInt(strA[i]); // 把strA的字符串转成整数
            int b = Integer.parseInt(strB[i]); // 把strB的字符串转成整数
            elements.add(new Element(a, b, i + 1)); // 封装成Element，索引从1开始
            sumA += a; // 累加A的总和
            sumB += b; // 累加B的总和
        }

        Collections.sort(elements, (e1, e2) -> {
            long s1 = (long) e1.a + e1.b;
            long s2 = (long) e2.a + e2.b;

            return Long.compare(s2, s1);// 按a+b从大到小排序
        });

        List<Integer> res = new ArrayList<>();
        long currentA = 0, currentB = 0;

        for (Element e : elements) {
            res.add(e.index); // 把当前元素的索引加入结果
            currentA += e.a; // 累加子集的A和
            currentB += e.b; // 累加子集的B和
            // 检查是否满足条件：子集和超过总和的一半
            if (currentA > sumA / 2 && currentB > sumB / 2) {
                break; // 满足条件则停止选取
            }
        }
        out.println(res.size());

        for (int i = 0; i < res.size(); i++) {
            out.print(res.get(i) + (i == res.size() - 1 ? "" : " "));
        }

        out.flush();
        out.close();
        br.close();
    }
}