在Arraylist的Arraylist中搜索

import java.util.ArrayList;

public class ArrayListSearch {
    public static void main(String[] args) {
        ArrayList<ArrayList<Integer>> arrayList = new ArrayList<>();

        // 添加元素到外层ArrayList
        arrayList.add(new ArrayList<>(List.of(1, 2, 3)));
        arrayList.add(new ArrayList<>(List.of(4, 5, 6)));
        arrayList.add(new ArrayList<>(List.of(7, 8, 9)));

        int target = 5;
        boolean found = false;
        int outerIndex = -1;
        int innerIndex = -1;

        // 遍历外层ArrayList
        for (int i = 0; i < arrayList.size(); i++) {
            ArrayList<Integer> innerList = arrayList.get(i);

            // 遍历内层ArrayList
            for (int j = 0; j < innerList.size(); j++) {
                int element = innerList.get(j);

                // 比较元素
                if (element == target) {
                    found = true;
                    outerIndex = i;
                    innerIndex = j;
                    break;
                }
            }

            if (found) {
                break;
            }
        }

        if (found) {
            System.out.println("元素 " + target + " 在外层ArrayList的索引为 " + outerIndex + "，内层ArrayList的索引为 " + innerIndex);
        } else {
            System.out.println("未找到元素 " + target);
        }
    }
}