diff --git a/solution/1300-1399/1399.Count Largest Group/README.md b/solution/1300-1399/1399.Count Largest Group/README.md
index ee880ec654ac2..a851ee797e8ff 100644
--- a/solution/1300-1399/1399.Count Largest Group/README.md	
+++ b/solution/1300-1399/1399.Count Largest Group/README.md	
@@ -74,7 +74,7 @@ tags:
 
 最后返回 $ans$ 即可。
 
-时间复杂度 $O(n \times \log M)$，空间复杂度 $(\log M)$。其中 $n$ 为给定的数字，而 $M$ 是 $n$ 的数字范围。
+时间复杂度 $O(n \times \log n)$，空间复杂度 $(\log n)$。其中 $n$ 为给定的数字。
 
 <!-- tabs:start -->
 
@@ -177,7 +177,7 @@ func countLargestGroup(n int) (ans int) {
 
 ```ts
 function countLargestGroup(n: number): number {
-    const cnt: number[] = new Array(40).fill(0);
+    const cnt: number[] = Array(40).fill(0);
     let mx = 0;
     let ans = 0;
     for (let i = 1; i <= n; ++i) {
@@ -197,6 +197,36 @@ function countLargestGroup(n: number): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn count_largest_group(n: i32) -> i32 {
+        let mut cnt = vec![0; 40];
+        let mut ans = 0;
+        let mut mx = 0;
+
+        for i in 1..=n {
+            let mut s = 0;
+            let mut x = i;
+            while x > 0 {
+                s += x % 10;
+                x /= 10;
+            }
+            cnt[s as usize] += 1;
+            if mx < cnt[s as usize] {
+                mx = cnt[s as usize];
+                ans = 1;
+            } else if mx == cnt[s as usize] {
+                ans += 1;
+            }
+        }
+
+        ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/1300-1399/1399.Count Largest Group/README_EN.md b/solution/1300-1399/1399.Count Largest Group/README_EN.md
index 4b9c648f3b6a5..c30865d5c0206 100644
--- a/solution/1300-1399/1399.Count Largest Group/README_EN.md	
+++ b/solution/1300-1399/1399.Count Largest Group/README_EN.md	
@@ -65,7 +65,7 @@ We enumerate each number in $[1,..n]$, calculate its sum of digits $s$, then inc
 
 Finally, we return $ans$.
 
-The time complexity is $O(n \times \log M)$, and the space complexity is $O(\log M)$. Where $n$ is the given number, and $M$ is the range of $n$.
+The time complexity is $O(n \times \log n)$, and the space complexity is $O(\log n)$, where $n$ is the given number.
 
 <!-- tabs:start -->
 
@@ -168,7 +168,7 @@ func countLargestGroup(n int) (ans int) {
 
 ```ts
 function countLargestGroup(n: number): number {
-    const cnt: number[] = new Array(40).fill(0);
+    const cnt: number[] = Array(40).fill(0);
     let mx = 0;
     let ans = 0;
     for (let i = 1; i <= n; ++i) {
@@ -188,6 +188,36 @@ function countLargestGroup(n: number): number {
 }
 ```
 
+#### Rust
+
+```rust
+impl Solution {
+    pub fn count_largest_group(n: i32) -> i32 {
+        let mut cnt = vec![0; 40];
+        let mut ans = 0;
+        let mut mx = 0;
+
+        for i in 1..=n {
+            let mut s = 0;
+            let mut x = i;
+            while x > 0 {
+                s += x % 10;
+                x /= 10;
+            }
+            cnt[s as usize] += 1;
+            if mx < cnt[s as usize] {
+                mx = cnt[s as usize];
+                ans = 1;
+            } else if mx == cnt[s as usize] {
+                ans += 1;
+            }
+        }
+
+        ans
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/1300-1399/1399.Count Largest Group/Solution.rs b/solution/1300-1399/1399.Count Largest Group/Solution.rs
new file mode 100644
index 0000000000000..9dd751501581a
--- /dev/null
+++ b/solution/1300-1399/1399.Count Largest Group/Solution.rs	
@@ -0,0 +1,25 @@
+impl Solution {
+    pub fn count_largest_group(n: i32) -> i32 {
+        let mut cnt = vec![0; 40];
+        let mut ans = 0;
+        let mut mx = 0;
+
+        for i in 1..=n {
+            let mut s = 0;
+            let mut x = i;
+            while x > 0 {
+                s += x % 10;
+                x /= 10;
+            }
+            cnt[s as usize] += 1;
+            if mx < cnt[s as usize] {
+                mx = cnt[s as usize];
+                ans = 1;
+            } else if mx == cnt[s as usize] {
+                ans += 1;
+            }
+        }
+
+        ans
+    }
+}
diff --git a/solution/1300-1399/1399.Count Largest Group/Solution.ts b/solution/1300-1399/1399.Count Largest Group/Solution.ts
index 44c9b6f05b7a2..c2c3401bf6970 100644
--- a/solution/1300-1399/1399.Count Largest Group/Solution.ts	
+++ b/solution/1300-1399/1399.Count Largest Group/Solution.ts	
@@ -1,5 +1,5 @@
 function countLargestGroup(n: number): number {
-    const cnt: number[] = new Array(40).fill(0);
+    const cnt: number[] = Array(40).fill(0);
     let mx = 0;
     let ans = 0;
     for (let i = 1; i <= n; ++i) {