示例 1：
输入：nums = [1,2,2,4]输出：[2,3]
来源：力扣（LeetCode）链接：https://leetcode-cn.com/problems/set-mismatch著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

    public int[] findErrorNums(int[] nums) {        int n = nums.length;        int[] arr = new int[n + 1];        int repeatedNum = 0;        for (int num : nums) {            arr[num] += 1;            if (arr[num] > 1) {                repeatedNum = num;            }        }        int lossNum = 0;        for (int i = 1; i <= n; i++) {            if (arr[i] == 0) {                lossNum = i;                break;            }        }        int[] ans = new int[2];        ans[0] = repeatedNum;        ans[1] = lossNum;
        return ans;    }