feat: add rust solution to lc problem: No.2609 (#1155)

Author: dierbei

solution/2600-2699/2609.Find the Longest Balanced Substring of a Binary String/README.md

@@ -335,6 +335,70 @@ function findTheLongestBalancedSubstring(s: string): number {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn find_the_longest_balanced_substring(s: String) -> i32 {
+        let check = |i: usize, j: usize| -> bool {
+            let mut cnt = 0;
+
+            for k in i..=j {
+                if s.as_bytes()[k] == b'1' {
+                    cnt += 1;
+                } else if cnt > 0 {
+                    return false
+                }
+            }
+
+            cnt * 2 == j - i + 1
+        };
+
+        let mut ans = 0;
+        let n = s.len();
+        for i in 0..n - 1 {
+            for j in (i + 1..n).rev() {
+                if j - i + 1 < ans {
+                    break;
+                }
+                
+                if check(i, j) {
+                    ans = std::cmp::max(ans, j - i + 1);
+                    break;
+                }
+            }
+        }
+
+        ans as i32
+    }
+}
+```
+
+```rust
+impl Solution {
+    pub fn find_the_longest_balanced_substring(s: String) -> i32 {
+        let mut zero = 0;
+        let mut one = 0;
+        let mut ans = 0;
+
+        for &c in s.as_bytes().iter() {
+            if c == b'0' {
+                if one > 0 {
+                    zero = 0;
+                    one = 0;
+                }
+                zero += 1;
+            } else {
+                one += 1;
+                ans = std::cmp::max(ans, std::cmp::min(zero, one) * 2)
+            }
+        }
+
+        ans
+    }
+}
+```
+
 ### **...**
 
 ```

solution/2600-2699/2609.Find the Longest Balanced Substring of a Binary String/README_EN.md

@@ -325,6 +325,70 @@ function findTheLongestBalancedSubstring(s: string): number {
 }
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn find_the_longest_balanced_substring(s: String) -> i32 {
+        let check = |i: usize, j: usize| -> bool {
+            let mut cnt = 0;
+
+            for k in i..=j {
+                if s.as_bytes()[k] == b'1' {
+                    cnt += 1;
+                } else if cnt > 0 {
+                    return false
+                }
+            }
+
+            cnt * 2 == j - i + 1
+        };
+
+        let mut ans = 0;
+        let n = s.len();
+        for i in 0..n - 1 {
+            for j in (i + 1..n).rev() {
+                if j - i + 1 < ans {
+                    break;
+                }
+                
+                if check(i, j) {
+                    ans = std::cmp::max(ans, j - i + 1);
+                    break;
+                }
+            }
+        }
+
+        ans as i32
+    }
+}
+```
+
+```rust
+impl Solution {
+    pub fn find_the_longest_balanced_substring(s: String) -> i32 {
+        let mut zero = 0;
+        let mut one = 0;
+        let mut ans = 0;
+
+        for &c in s.as_bytes().iter() {
+            if c == b'0' {
+                if one > 0 {
+                    zero = 0;
+                    one = 0;
+                }
+                zero += 1;
+            } else {
+                one += 1;
+                ans = std::cmp::max(ans, std::cmp::min(zero, one) * 2)
+            }
+        }
+
+        ans
+    }
+}
+```
+
 ### **...**
 
 ```

solution/2600-2699/2609.Find the Longest Balanced Substring of a Binary String/Solution.rs

@@ -0,0 +1,22 @@
+impl Solution {
+    pub fn find_the_longest_balanced_substring(s: String) -> i32 {
+        let mut zero = 0;
+        let mut one = 0;
+        let mut ans = 0;
+
+        for &c in s.as_bytes().iter() {
+            if c == b'0' {
+                if one > 0 {
+                    zero = 0;
+                    one = 0;
+                }
+                zero += 1;
+            } else {
+                one += 1;
+                ans = std::cmp::max(ans, std::cmp::min(zero, one) * 2)
+            }
+        }
+
+        ans
+    }
+}