@[wangbohan13782700406](/user/999070)
```cpp
#include <cstdio>
#include <algorithm>
int arr[200005];
int main() {
int n;
scanf("%d", &n);
for (int i = 0; i < n; i++) scanf("%d", arr + i);
std::sort(arr, arr + n);
int* pos = std::unique(arr, arr + n);
printf("%d\n", pos - arr);
for (int *it = arr; it != pos; ++it) printf("%d ", *it);
}
```
by Ruiqun2009 @ 2023-05-02 16:01:29
@[Ruiqun2009](/user/589895)
谢大神
by wangbohan13782700406 @ 2023-05-02 16:45:02