LeetCode45|数组中重复的数据

输入:
[4,3,2,7,8,2,3,1]

输出:
[2,3]

 
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class FindDuplicatesTest {
    public static void main(String[] args) {
        int[] nums = {4, 3, 2, 7, 8, 2, 3, 1};
        List<Integer> integerList = findDuplicates(nums);
        System.out.println("integerList = " + integerList);
    }

    public static List<Integer> findDuplicates(int[] nums) {
        List<Integer> list = new ArrayList<>();
        if (nums == null || nums.length == 0) {
            return list;

        }
        int maxValue = Arrays.stream(nums).max().getAsInt();
        int[] array = new int[maxValue + 1];
        for (int num : nums) {
            array[num]++;
        }
        for (int i = 0, length = array.length; i < length; i++) {
            if (array[i] == 2) {
                list.add(i);
            }
        }

        return list;
    }
}