diff --git a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README.md b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README.md
index 73dab77aa66b1..2eb800baa892b 100644
--- a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README.md	
+++ b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README.md	
@@ -183,19 +183,19 @@ func maxVowels(s string, k int) int {
 
 ```ts
 function maxVowels(s: string, k: number): number {
-    const isVowel = (c: string) => ['a', 'e', 'i', 'o', 'u'].includes(c);
+    const vowels = new Set(['a', 'e', 'i', 'o', 'u']);
     let cnt = 0;
     for (let i = 0; i < k; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
     }
     let ans = cnt;
     for (let i = k; i < s.length; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
-        if (isVowel(s[i - k])) {
+        if (vowels.has(s[i - k])) {
             cnt--;
         }
         ans = Math.max(ans, cnt);
diff --git a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README_EN.md b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README_EN.md
index 0369f8fcec7d6..5400edd63a71a 100644
--- a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README_EN.md	
+++ b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/README_EN.md	
@@ -169,19 +169,19 @@ func maxVowels(s string, k int) int {
 
 ```ts
 function maxVowels(s: string, k: number): number {
-    const isVowel = (c: string) => ['a', 'e', 'i', 'o', 'u'].includes(c);
+    const vowels = new Set(['a', 'e', 'i', 'o', 'u']);
     let cnt = 0;
     for (let i = 0; i < k; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
     }
     let ans = cnt;
     for (let i = k; i < s.length; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
-        if (isVowel(s[i - k])) {
+        if (vowels.has(s[i - k])) {
             cnt--;
         }
         ans = Math.max(ans, cnt);
diff --git a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/Solution.ts b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/Solution.ts
index 93449f8d6d245..1ecc2e4dff56b 100644
--- a/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/Solution.ts	
+++ b/solution/1400-1499/1456.Maximum Number of Vowels in a Substring of Given Length/Solution.ts	
@@ -1,17 +1,17 @@
 function maxVowels(s: string, k: number): number {
-    const isVowel = (c: string) => ['a', 'e', 'i', 'o', 'u'].includes(c);
+    const vowels = new Set(['a', 'e', 'i', 'o', 'u']);
     let cnt = 0;
     for (let i = 0; i < k; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
     }
     let ans = cnt;
     for (let i = k; i < s.length; i++) {
-        if (isVowel(s[i])) {
+        if (vowels.has(s[i])) {
             cnt++;
         }
-        if (isVowel(s[i - k])) {
+        if (vowels.has(s[i - k])) {
             cnt--;
         }
         ans = Math.max(ans, cnt);