Skip to content

Sub Sets #29

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
rossy0213 wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Sub Sets #29

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Empty file added SubSets/step1.md
View file
Open in desktop
Empty file.
19 changes: 19 additions & 0 deletions SubSets/step2.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
```java
Copy link
Copy Markdown

@oda oda Jul 29, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

これも再帰の仕方が何種類かあるように思います。あとループに直せるといいと思います。

// Time spend: 02:01
class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> res = new ArrayList<>();
backtrack(res, new ArrayList<>(), nums, 0);
return res;
}

private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
Copy link
Copy Markdown

@goto-untrapped goto-untrapped Jul 30, 2024

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

tempList が気になってしまいました。
backtrack() を呼ぶごとに1つの組み合わせとして res に add() しているので、subset とかでもいいかもしれません。
と、すみません backtrack() も気になりました。
makeSubsets() とか、何かしら付けるといいかもしれません。

res.add(new ArrayList<>(tempList));
for (int i = start; i < nums.length; i++) {
tempList.add(nums[i]);
backtrack(res, tempList, nums, i + 1);
tempList.remove(tempList.size() - 1);
}
}
}
```
59 changes: 59 additions & 0 deletions SubSets/step3.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,59 @@
```java
// Time spend: 01:41
class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> res = new ArrayList<>();
backtrack(res, new ArrayList<>(), nums, 0);
return res;
}

private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
res.add(new ArrayList<>(tempList));
for (int i = start; i < nums.length; i++) {
tempList.add(nums[i]);
backtrack(res, tempList, nums, i + 1);
tempList.remove(tempList.size() - 1);
}
}
}
```

```java
// Time spend: 01:51
class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> res = new ArrayList<>();
backtrack(res, new ArrayList<>(), nums, 0);
return res;
}

private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
res.add(new ArrayList<>(tempList));
for (int i = start; i < nums.length; i++) {
tempList.add(nums[i]);
backtrack(res, tempList, nums, i + 1);
tempList.remove(tempList.size() - 1);
}
}
}
```

```java
// Time spend: 01:23
class Solution {
public List<List<Integer>> subsets(int[] nums) {
List<List<Integer>> res = new ArrayList<>();
backtrack(res, new ArrayList<>(), nums, 0);
return res;
}

private void backtrack(List<List<Integer>> res, List<Integer> tempList, int[] nums, int start) {
res.add(new ArrayList<>(tempList));
for (int i = start; i < nums.length; i++) {
tempList.add(nums[i]);
backtrack(res, tempList, nums, i + 1);
tempList.remove(tempList.size() - 1);
}
}
}
```