From c35240d871cb560a809b0d6efec9b1d84275be9f Mon Sep 17 00:00:00 2001
From: rossy0213 <bieshan0213+github@gmail.com>
Date: Tue, 4 Jun 2024 00:54:24 +0900
Subject: [PATCH] Generate Parentheses

---
 GenerateParentheses/step1.md | 30 ++++++++++++++
 GenerateParentheses/step2.md | 25 ++++++++++++
 GenerateParentheses/step3.md | 77 ++++++++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+)
 create mode 100644 GenerateParentheses/step1.md
 create mode 100644 GenerateParentheses/step2.md
 create mode 100644 GenerateParentheses/step3.md

diff --git a/GenerateParentheses/step1.md b/GenerateParentheses/step1.md
new file mode 100644
index 0000000..081cd78
--- /dev/null
+++ b/GenerateParentheses/step1.md
@@ -0,0 +1,30 @@
+```java
+// Until reach to the max length(n * 2)
+// We try to add left part first then add right side
+// Until number of left part reach to n, we can add left part
+// And if number of left part is bigger than right part, we can try to add right part
+// Time complexity: O(2**(N*2)) 
+// Space complexity: O(n) stack memory for backtack
+// Time spend: XX(Found the answer after checking Solutions tab)
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> res = new ArrayList<>();
+        generateParenthesis(res, 0, 0, "", n);
+        return res;
+    }
+
+    public void generateParenthesis(List<String> res, int l, int r, String curr,int n) {
+        if (curr.length() == n * 2) {
+            res.add(curr);
+            return;
+        }
+
+        if (l < n) {
+            generateParenthesis(res, l + 1, r, curr + "(", n);
+        }
+        if (r < l) {
+            generateParenthesis(res, l, r + 1, curr + ")", n);
+        }
+    }
+}
+```
\ No newline at end of file
diff --git a/GenerateParentheses/step2.md b/GenerateParentheses/step2.md
new file mode 100644
index 0000000..492e41f
--- /dev/null
+++ b/GenerateParentheses/step2.md
@@ -0,0 +1,25 @@
+```java
+// Time spend: 01:47
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> res = new ArrayList<>();
+        generateParenthesis(res, 0, 0, n, "");
+        return res;
+    }
+
+    public void generateParenthesis(List<String> res, int l, int r, int n, String curr) {
+        if (curr.length() == n * 2) {
+            res.add(curr);
+            return;
+        }
+
+        if (l < n) {
+            generateParenthesis(res, l + 1, r, n, curr + '(');
+        }
+
+        if (r < l) {
+            generateParenthesis(res, l, r + 1, n, curr + ')');
+        }
+    }
+}
+```
\ No newline at end of file
diff --git a/GenerateParentheses/step3.md b/GenerateParentheses/step3.md
new file mode 100644
index 0000000..b71884a
--- /dev/null
+++ b/GenerateParentheses/step3.md
@@ -0,0 +1,77 @@
+```java
+// Time spend: 01:33
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> res = new ArrayList<>();
+        generateParenthesis(res, 0, 0, n, "");
+        return res;
+    }
+
+    public void generateParenthesis(List<String> res, int l, int r, int n, String curr) {
+        if (curr.length() == n * 2) {
+            res.add(curr);
+            return;
+        }
+
+        if (l < n) {
+            generateParenthesis(res, l + 1, r, n, curr + '(');
+        }
+
+        if (r < l) {
+            generateParenthesis(res, l, r + 1, n, curr + ')');
+        }
+    }
+}
+```
+
+```java
+// Time spend: 01:37
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> res = new ArrayList<>();
+        generateParenthesis(res, 0, 0, n, "");
+        return res;
+    }
+
+    public void generateParenthesis(List<String> res, int l, int r, int n, String curr) {
+        if (curr.length() == n * 2) {
+            res.add(curr);
+            return;
+        }
+
+        if (l < n) {
+            generateParenthesis(res, l + 1, r, n, curr + '(');
+        }
+
+        if (r < l) {
+            generateParenthesis(res, l, r + 1, n, curr + ')');
+        }
+    }
+}
+```
+
+```java
+// Time spend: 01:26
+class Solution {
+    public List<String> generateParenthesis(int n) {
+        List<String> res = new ArrayList<>();
+        generateParenthesis(res, 0, 0, n, "");
+        return res;
+    }
+
+    public void generateParenthesis(List<String> res, int l, int r, int n, String curr) {
+        if (curr.length() == n * 2) {
+            res.add(curr);
+            return;
+        }
+
+        if (l < n) {
+            generateParenthesis(res, l + 1, r, n, curr + '(');
+        }
+
+        if (r < l) {
+            generateParenthesis(res, l, r + 1, n, curr + ')');
+        }
+    }
+}
+```
\ No newline at end of file