feat: add Rust solution for lc No.3713

Author: yanglbme

solution/3700-3799/3713.Longest Balanced Substring I/README.md

@@ -215,6 +215,41 @@ function longestBalanced(s: string): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn longest_balanced(s: String) -> i32 {
+        let n: i32 = s.len() as i32;
+        let bytes = s.as_bytes();
+        let mut ans: i32 = 0;
+
+        for i in 0..n {
+            let mut cnt: [i32; 26] = [0; 26];
+            let mut mx: i32 = 0;
+            let mut v: i32 = 0;
+
+            for j in i..n {
+                let c: usize = (bytes[j as usize] - b'a') as usize;
+                cnt[c] += 1;
+
+                if cnt[c] == 1 {
+                    v += 1;
+                }
+
+                mx = mx.max(cnt[c]);
+
+                if mx * v == j - i + 1 {
+                    ans = ans.max(j - i + 1);
+                }
+            }
+        }
+
+        ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/3700-3799/3713.Longest Balanced Substring I/README_EN.md

@@ -210,6 +210,41 @@ function longestBalanced(s: string): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn longest_balanced(s: String) -> i32 {
+        let n: i32 = s.len() as i32;
+        let bytes = s.as_bytes();
+        let mut ans: i32 = 0;
+
+        for i in 0..n {
+            let mut cnt: [i32; 26] = [0; 26];
+            let mut mx: i32 = 0;
+            let mut v: i32 = 0;
+
+            for j in i..n {
+                let c: usize = (bytes[j as usize] - b'a') as usize;
+                cnt[c] += 1;
+
+                if cnt[c] == 1 {
+                    v += 1;
+                }
+
+                mx = mx.max(cnt[c]);
+
+                if mx * v == j - i + 1 {
+                    ans = ans.max(j - i + 1);
+                }
+            }
+        }
+
+        ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/3700-3799/3713.Longest Balanced Substring I/Solution.rs

@@ -0,0 +1,30 @@
+impl Solution {
+    pub fn longest_balanced(s: String) -> i32 {
+        let n: i32 = s.len() as i32;
+        let bytes = s.as_bytes();
+        let mut ans: i32 = 0;
+
+        for i in 0..n {
+            let mut cnt: [i32; 26] = [0; 26];
+            let mut mx: i32 = 0;
+            let mut v: i32 = 0;
+
+            for j in i..n {
+                let c: usize = (bytes[j as usize] - b'a') as usize;
+                cnt[c] += 1;
+
+                if cnt[c] == 1 {
+                    v += 1;
+                }
+
+                mx = mx.max(cnt[c]);
+
+                if mx * v == j - i + 1 {
+                    ans = ans.max(j - i + 1);
+                }
+            }
+        }
+
+        ans
+    }
+}