From e82a197cbe277ba4beee4df958a226bac5bb795d Mon Sep 17 00:00:00 2001
From: colorbox <colorbox222@gmail.com>
Date: Tue, 12 Mar 2024 02:57:37 +0900
Subject: [PATCH 1/2] Add solved codes

---
 20/1.cpp | 20 ++++++++++++++++++++
 20/2.cpp | 19 +++++++++++++++++++
 20/3.cpp | 20 ++++++++++++++++++++
 3 files changed, 59 insertions(+)
 create mode 100644 20/1.cpp
 create mode 100644 20/2.cpp
 create mode 100644 20/3.cpp

diff --git a/20/1.cpp b/20/1.cpp
new file mode 100644
index 0000000..5a922a9
--- /dev/null
+++ b/20/1.cpp
@@ -0,0 +1,20 @@
+class Solution {
+public:
+    bool isValid(string s) {
+        stack<char> stack;
+
+        for(char c : s){
+            // stack topとのチェック
+            if(!stack.empty() && isPair(stack.top(), c)){
+                stack.pop();
+            }else{
+                stack.push(c);
+            }
+        }
+        return stack.empty();
+    }
+
+    bool isPair(char l, char r){
+        return (l == '(' && r == ')' || l == '{' && r == '}' || l == '[' && r == ']');
+    }
+};
diff --git a/20/2.cpp b/20/2.cpp
new file mode 100644
index 0000000..59cf18f
--- /dev/null
+++ b/20/2.cpp
@@ -0,0 +1,19 @@
+class Solution {
+public:
+    bool isValid(string s) {
+        stack<char> stack;
+
+        for(char c : s){
+            if(!stack.empty() && isPair(stack.top(), c)){
+                stack.pop();
+            }else{
+                stack.push(c);
+            }
+        }
+        return stack.empty();
+    }
+
+    bool isPair(char l, char r){
+        return (l == '(' && r == ')' || l == '{' && r == '}' || l == '[' && r == ']');
+    }
+};
diff --git a/20/3.cpp b/20/3.cpp
new file mode 100644
index 0000000..332501b
--- /dev/null
+++ b/20/3.cpp
@@ -0,0 +1,20 @@
+class Solution {
+public:
+    bool isValid(string s) {
+        stack<char> stack;
+
+        for(char c: s){
+            if(!stack.empty() && isPair(stack.top(), c)){
+                stack.pop();
+            }else{
+                stack.push(c);
+            }
+        }
+
+        return stack.empty();
+    }
+
+    bool isPair(char l, char r){
+        return (l == '{' && r == '}' || l == '(' && r == ')' || l == '[' && r == ']');
+    }
+};

From f080d2a942567275e8383797ed5bfe58f9e5ecb1 Mon Sep 17 00:00:00 2001
From: colorbox <colorbox222@gmail.com>
Date: Wed, 13 Mar 2024 02:13:58 +0900
Subject: [PATCH 2/2] =?UTF-8?q?=E3=83=AC=E3=83=93=E3=83=A5=E3=83=BC?=
 =?UTF-8?q?=E3=81=AE=E6=8C=87=E6=91=98=E4=BA=8B=E9=A0=85=E3=82=92=E7=9B=9B?=
 =?UTF-8?q?=E3=82=8A=E8=BE=BC=E3=82=93=E3=81=A0=E6=94=B9=E8=89=AF=E3=82=B3?=
 =?UTF-8?q?=E3=83=BC=E3=83=89=E3=82=92=E8=BF=BD=E5=8A=A0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 20/4.cpp | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 20/4.cpp

diff --git a/20/4.cpp b/20/4.cpp
new file mode 100644
index 0000000..8235c7d
--- /dev/null
+++ b/20/4.cpp
@@ -0,0 +1,29 @@
+class Solution {
+public:
+    bool isValid(string s) {
+        stack<char> stack;
+
+        if(s[0] == ')' || s[0] == '}' || s[0] == ']'){
+            return false;
+        }
+
+        for(char c : s){
+            if(!stack.empty() && isInvalidPair(stack.top(), c)){return false;}
+            
+            if(c != '(' && c != '{' && c != '[' && !stack.empty() && isPair(stack.top(), c)){
+                stack.pop();
+            }else{
+                stack.push(c);
+            }
+        }
+        return stack.empty();
+    }
+
+    bool isPair(char l, char r){
+        return (l == '(' && r == ')' || l == '{' && r == '}' || l == '[' && r == ']');
+    }
+
+    bool isInvalidPair(char l, char r){
+        return (l == '(' && (r == '}' || r == ']')) || (l == '{' && (r == ')' || r == ']')) || (l == '[' && (r == '}' || r == ')'));
+    }
+};