From 52b4945432bc093273b8e9270f7b213c7170edba Mon Sep 17 00:00:00 2001
From: Pandurang Lad <premlad961@gmail.com>
Date: Sun, 5 Nov 2023 13:37:57 +0530
Subject: [PATCH 1/3] feat: update README_EN.md to lc problem: No.0020

---
 .../0020.Valid Parentheses/README_EN.md       | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/solution/0000-0099/0020.Valid Parentheses/README_EN.md b/solution/0000-0099/0020.Valid Parentheses/README_EN.md
index 577d9fa916a5f..440739c3d7fb7 100644
--- a/solution/0000-0099/0020.Valid Parentheses/README_EN.md	
+++ b/solution/0000-0099/0020.Valid Parentheses/README_EN.md	
@@ -230,6 +230,27 @@ impl Solution {
 }
 ```
 
+### **C#**
+
+```C#
+public class Solution {
+    public bool IsValid(string s) {
+        Stack<char> ch = new Stack<char>();
+            foreach (var item in s.ToCharArray())
+                if (item == '(')
+                    ch.Push(')');
+                else if (item == '[')
+                    ch.Push(']');
+                else if (item == '{')
+                    ch.Push('}');
+                else if (ch.Count == 0 || ch.Pop() != item)
+                    return false;
+
+            return ch.Count == 0;
+    }
+}
+```
+
 ### **...**
 
 ```

From 1141943662ff1c2cf30b653e065a3326e5ef0d27 Mon Sep 17 00:00:00 2001
From: Libin YANG <contact@yanglibin.info>
Date: Sun, 5 Nov 2023 22:59:11 +0800
Subject: [PATCH 2/3] Update README_EN.md

---
 .../0020.Valid Parentheses/README_EN.md       | 27 ++++++++++---------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/solution/0000-0099/0020.Valid Parentheses/README_EN.md b/solution/0000-0099/0020.Valid Parentheses/README_EN.md
index 440739c3d7fb7..55aed31cf83be 100644
--- a/solution/0000-0099/0020.Valid Parentheses/README_EN.md	
+++ b/solution/0000-0099/0020.Valid Parentheses/README_EN.md	
@@ -232,21 +232,22 @@ impl Solution {
 
 ### **C#**
 
-```C#
+```cs
 public class Solution {
     public bool IsValid(string s) {
-        Stack<char> ch = new Stack<char>();
-            foreach (var item in s.ToCharArray())
-                if (item == '(')
-                    ch.Push(')');
-                else if (item == '[')
-                    ch.Push(']');
-                else if (item == '{')
-                    ch.Push('}');
-                else if (ch.Count == 0 || ch.Pop() != item)
-                    return false;
-
-            return ch.Count == 0;
+        Stack<char> stk = new Stack<char>();
+        foreach (var c in s.ToCharArray()) {
+            if (c == '(') {
+                stk.Push(')');
+            } else if (c == '[') {
+                stk.Push(']');
+            } else if (c == '{') {
+                stk.Push('}');
+            } else if (stk.Count == 0 || stk.Pop() != c) {
+                return false;
+            }
+        }
+        return stk.Count == 0;
     }
 }
 ```

From febd23820af2ab4bff2f12d4ecc8890fd74ccf9b Mon Sep 17 00:00:00 2001
From: Libin YANG <contact@yanglibin.info>
Date: Sun, 5 Nov 2023 22:59:40 +0800
Subject: [PATCH 3/3] Update README.md

---
 .../0020.Valid Parentheses/README.md          | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/solution/0000-0099/0020.Valid Parentheses/README.md b/solution/0000-0099/0020.Valid Parentheses/README.md
index de50710ecfec9..90c196ebc2976 100644
--- a/solution/0000-0099/0020.Valid Parentheses/README.md	
+++ b/solution/0000-0099/0020.Valid Parentheses/README.md	
@@ -252,6 +252,28 @@ impl Solution {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public bool IsValid(string s) {
+        Stack<char> stk = new Stack<char>();
+        foreach (var c in s.ToCharArray()) {
+            if (c == '(') {
+                stk.Push(')');
+            } else if (c == '[') {
+                stk.Push(']');
+            } else if (c == '{') {
+                stk.Push('}');
+            } else if (stk.Count == 0 || stk.Pop() != c) {
+                return false;
+            }
+        }
+        return stk.Count == 0;
+    }
+}
+```
+
 ### **...**
 
 ```