From 555303750f3fd5077783a1042ba5cbff03a0f685 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Velimir=20=C4=90urkovi=C4=87?= <velimir.djurkovic@gmail.com>
Date: Fri, 7 Feb 2025 16:31:11 +0100
Subject: [PATCH] feat: add solution to lc problem: No.0005

---
 .../README.md                                 | 33 +++++++++++++++++++
 .../README_EN.md                              | 33 +++++++++++++++++++
 .../Solution2.cs                              | 28 ++++++++++++++++
 3 files changed, 94 insertions(+)
 create mode 100644 solution/0000-0099/0005.Longest Palindromic Substring/Solution2.cs

diff --git a/solution/0000-0099/0005.Longest Palindromic Substring/README.md b/solution/0000-0099/0005.Longest Palindromic Substring/README.md
index 407fd7e12412c..11a6b7df01a67 100644
--- a/solution/0000-0099/0005.Longest Palindromic Substring/README.md	
+++ b/solution/0000-0099/0005.Longest Palindromic Substring/README.md	
@@ -456,6 +456,39 @@ impl Solution {
 }
 ```
 
+#### C#
+
+```cs
+public class Solution {
+    private string s;
+    private int n;
+
+    public String LongestPalindrome(string s) {
+        this.s = s;
+        n = s.Length;
+        int start = 0, mx = 1;
+        for (int i = 0; i < n; ++i) {
+            int a = F(i, i);
+            int b = F(i, i + 1);
+            int t = Math.Max(a, b);
+            if (mx < t) {
+                mx = t;
+                start = i - ((t - 1) >> 1);
+            }
+        }
+        return s.Substring(start, start + mx);
+    }
+
+    private int F(int l, int r) {
+        while (l >= 0 && r < n && s[l] == s[r]) {
+            --l;
+            ++r;
+        }
+        return r - l - 1;
+    }
+}
+```
+
 #### PHP
 
 ```php
diff --git a/solution/0000-0099/0005.Longest Palindromic Substring/README_EN.md b/solution/0000-0099/0005.Longest Palindromic Substring/README_EN.md
index 895bbb34ed3ff..4ac2610fb4e8e 100644
--- a/solution/0000-0099/0005.Longest Palindromic Substring/README_EN.md	
+++ b/solution/0000-0099/0005.Longest Palindromic Substring/README_EN.md	
@@ -454,6 +454,39 @@ impl Solution {
 }
 ```
 
+#### C#
+
+```cs
+public class Solution {
+    private string s;
+    private int n;
+
+    public String LongestPalindrome(string s) {
+        this.s = s;
+        n = s.Length;
+        int start = 0, mx = 1;
+        for (int i = 0; i < n; ++i) {
+            int a = F(i, i);
+            int b = F(i, i + 1);
+            int t = Math.Max(a, b);
+            if (mx < t) {
+                mx = t;
+                start = i - ((t - 1) >> 1);
+            }
+        }
+        return s.Substring(start, start + mx);
+    }
+
+    private int F(int l, int r) {
+        while (l >= 0 && r < n && s[l] == s[r]) {
+            --l;
+            ++r;
+        }
+        return r - l - 1;
+    }
+}
+```
+
 #### PHP
 
 ```php
diff --git a/solution/0000-0099/0005.Longest Palindromic Substring/Solution2.cs b/solution/0000-0099/0005.Longest Palindromic Substring/Solution2.cs
new file mode 100644
index 0000000000000..48e1cf8b8e46c
--- /dev/null
+++ b/solution/0000-0099/0005.Longest Palindromic Substring/Solution2.cs	
@@ -0,0 +1,28 @@
+public class Solution {
+    private string s;
+    private int n;
+
+    public String LongestPalindrome(string s) {
+        this.s = s;
+        n = s.Length;
+        int start = 0, mx = 1;
+        for (int i = 0; i < n; ++i) {
+            int a = F(i, i);
+            int b = F(i, i + 1);
+            int t = Math.Max(a, b);
+            if (mx < t) {
+                mx = t;
+                start = i - ((t - 1) >> 1);
+            }
+        }
+        return s.Substring(start, start + mx);
+    }
+
+    private int F(int l, int r) {
+        while (l >= 0 && r < n && s[l] == s[r]) {
+            --l;
+            ++r;
+        }
+        return r - l - 1;
+    }
+}
\ No newline at end of file