feat: add cs solution to lc problem: No.1759 (#1947)

Author: dev-mauli

solution/1700-1799/1759.Count Number of Homogenous Substrings/README.md

@@ -268,6 +268,27 @@ int countHomogenous(char* s) {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int CountHomogenous(string s) {
+        long MOD = 1000000007;
+        long ans = 0;
+        for (int i = 0, j = 0; i < s.Length; i = j) {
+            j = i;
+            while (j < s.Length && s[j] == s[i]) {
+                ++j;
+            }
+            int cnt = j - i;
+            ans += (long) (1 + cnt) * cnt / 2;
+            ans %= MOD;
+        }
+        return (int) ans;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1700-1799/1759.Count Number of Homogenous Substrings/README_EN.md

@@ -250,6 +250,27 @@ int countHomogenous(char* s) {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int CountHomogenous(string s) {
+        long MOD = 1000000007;
+        long ans = 0;
+        for (int i = 0, j = 0; i < s.Length; i = j) {
+            j = i;
+            while (j < s.Length && s[j] == s[i]) {
+                ++j;
+            }
+            int cnt = j - i;
+            ans += (long) (1 + cnt) * cnt / 2;
+            ans %= MOD;
+        }
+        return (int) ans;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1700-1799/1759.Count Number of Homogenous Substrings/Solution.cs

@@ -0,0 +1,16 @@
+public class Solution {
+    public int CountHomogenous(string s) {
+        long MOD = 1000000007;
+        long ans = 0;
+        for (int i = 0, j = 0; i < s.Length; i = j) {
+            j = i;
+            while (j < s.Length && s[j] == s[i]) {
+                ++j;
+            }
+            int cnt = j - i;
+            ans += (long) (1 + cnt) * cnt / 2;
+            ans %= MOD;
+        }
+        return (int) ans;
+    }
+}