From ca4fe2293d38110a07e294726d6ab62615f13dee Mon Sep 17 00:00:00 2001
From: Sainnhe Park <i@sainnhe.dev>
Date: Thu, 2 Feb 2023 18:53:00 +0800
Subject: [PATCH] s0078

---
 include/s0078_subsets.hpp | 13 +++++++++++++
 notes/src/SUMMARY.md      |  1 +
 notes/src/subsets.md      |  5 +++++
 src/s0078_subsets.cpp     | 22 ++++++++++++++++++++++
 4 files changed, 41 insertions(+)
 create mode 100644 include/s0078_subsets.hpp
 create mode 100644 notes/src/subsets.md
 create mode 100644 src/s0078_subsets.cpp

diff --git a/include/s0078_subsets.hpp b/include/s0078_subsets.hpp
new file mode 100644
index 0000000..a1cfed2
--- /dev/null
+++ b/include/s0078_subsets.hpp
@@ -0,0 +1,13 @@
+#ifndef S0078_SUBSETS_HPP
+#define S0078_SUBSETS_HPP
+
+#include <vector>
+
+using namespace std;
+
+class S0078 {
+ public:
+  vector<vector<int>> subsets(vector<int>& nums);
+};
+
+#endif
diff --git a/notes/src/SUMMARY.md b/notes/src/SUMMARY.md
index 9c602c4..600c238 100644
--- a/notes/src/SUMMARY.md
+++ b/notes/src/SUMMARY.md
@@ -43,6 +43,7 @@
 - [总结](./backtrack.md)
 - [组合问题](./combinations.md)
 - [切割问题](./split.md)
+- [子集问题](./subsets.md)
 
 # STL
 
diff --git a/notes/src/subsets.md b/notes/src/subsets.md
new file mode 100644
index 0000000..4eaa8ac
--- /dev/null
+++ b/notes/src/subsets.md
@@ -0,0 +1,5 @@
+# 子集问题
+
+## [78. 子集](https://leetcode.cn/problems/subsets/)
+
+其实和切割问题非常像。
diff --git a/src/s0078_subsets.cpp b/src/s0078_subsets.cpp
new file mode 100644
index 0000000..ad2cf92
--- /dev/null
+++ b/src/s0078_subsets.cpp
@@ -0,0 +1,22 @@
+#include "s0078_subsets.hpp"
+
+void subsetsDFS(vector<int> &subset, vector<vector<int>> &result, vector<int> &nums, int startIndex) {
+  int size = nums.size();
+  // 结束条件
+  if (startIndex == size) return;
+
+  for (int i = startIndex; i < size; ++i) {
+    subset.push_back(nums[i]);
+    result.push_back(subset);
+    subsetsDFS(subset, result, nums, i + 1);
+    subset.pop_back();
+  }
+}
+
+vector<vector<int>> S0078::subsets(vector<int>& nums) {
+  vector<int> subset{};
+  vector<vector<int>> result{};
+  subsetsDFS(subset, result, nums, 0);
+  result.push_back(vector<int>{});
+  return result;
+}