```
public int[] findErrorNums(int[] nums) {
int[] res = new int[2];
int[] count = new int[nums.length + 1];
for (int i = 0; i < nums.length; i++) count[nums[i]]++;
for (int i = 1; i < count.length; i++) {
if (count[i] == 2) res[0] = i;
if (count[i] == 0) res[1] = i;
}
return res;
}
```