> For the complete documentation index, see [llms.txt](https://liuyang89116.gitbook.io/my-leetcode-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://liuyang89116.gitbook.io/my-leetcode-book/chapter_1_combination_and_permutation/pai_lie_zu_he_mo_ban.md).

# Summary 1: Template

## 这是一段经典的排列组合模板。

```java
void subsets(int[] num) {
    ArrayList<Integer> path = new ArrayList<Integer>();
    Arrays.sort(num);
    subsetsHelper(path, num, 0);
}

void subsetsHelper(ArrayList<Integer> path, int[] num, int pos) {
    outputToResult(path);

    for (int i = pos; i < num.length; i++) {
        path.add(num[i]);
        subsetsHelper(path, num, i + 1);
        path.remove(path.size() - 1);
    }
}
```