⚡ improve: prefer Unit32Array instead of number[]

Author: guanghechen

Diff for: packages/manacher/README.md

@@ -85,16 +85,16 @@ If you are interested in this algorithm, you can check [here][manacher].
   ```typescript
   import manacher from '@algorithm.ts/manacher'
 
-  export function minCut(s: string): number {
-    const N: number = s.length
-    const f: number[] = manacher(s)
+  export function minCut(text: string): number {
+    const N: number = text.length
+    const radius: Uint32Array= manacher(text)
     const dp: Uint32Array = new Uint32Array(N)
 
     for (let i = 1; i < N; ++i) {
-      let answer: number = i < f[i] * 2 ? 0 : dp[i - 1] + 1
+      let answer: number = i < radius[i] * 2 ? 0 : dp[i - 1] + 1
       if (answer > 0) {
         for (let k = 1; k < i; ++k) {
-          if (i - k < f[i + k] * 2) {
+          if (i - k < radius[i + k] * 2) {
             answer = Math.min(answer, dp[k - 1] + 1)
           }
         }

Diff for: packages/manacher/__test__/manacher.spec.ts

@@ -39,14 +39,14 @@ test('manacher', function () {
  */
 function solution1(text: string): number {
   const N: number = text.length
-  const f: number[] = manacher(text)
+  const radius: Uint32Array = manacher(text)
   const dp: Uint32Array = new Uint32Array(N)
 
   for (let i = 1; i < N; ++i) {
-    let answer: number = i < f[i] * 2 ? 0 : dp[i - 1] + 1
+    let answer: number = i < radius[i] * 2 ? 0 : dp[i - 1] + 1
     if (answer > 0) {
       for (let k = 1; k < i; ++k) {
-        if (i - k < f[i + k] * 2) {
+        if (i - k < radius[i + k] * 2) {
           answer = Math.min(answer, dp[k - 1] + 1)
         }
       }

Diff for: packages/manacher/src/index.ts

@@ -2,13 +2,13 @@
  * Find the longest palindrome length centered at each position in the given
  * text string within the complexity of $O(N)$.
  *
- * Note: len is an array with a length of $2N-1$, which represents the radius
+ * Note: radius is an array with a length of $2N-1$, which represents the radius
  * of the palindrome:
  *
- *  - len[2i] is equal to the radius of the longest palindrome centered at
+ *  - radius[2i] is equal to the radius of the longest palindrome centered at
  *    the position (i, i)
  *
- *  - len[2i+1] is equal to the radius of the longest palindrome centered at
+ *  - radius[2i+1] is equal to the radius of the longest palindrome centered at
  *    the position (i, i+1)
  *
  * ## Examples
@@ -17,34 +17,34 @@
  *
  *  ==>
  *
- *  len[3] = 2   // abba
- *  len[6] = 2   // bab
+ *  radius[3] = 2   // abba
+ *  radius[6] = 2   // bab
  *
  * @param text
- * @param len
+ * @param radius
  * @param N
  *
  * @see https://me.guanghechen.com/post/algorithm/string/manacher/
  */
-export function manacher(text: string): number[] {
+export function manacher(text: string): Uint32Array {
   const N = text.length
-  const _size = N * 2 - 1
-  const len: number[] = new Array(_size)
+  const _size = (N << 1) - 1
+  const radius: Uint32Array = new Uint32Array(_size)
 
-  len[0] = 1
+  radius[0] = 1
   for (let i = 1, j = 0; i < _size; ++i) {
     const p: number = i >> 1
     const q: number = i - p
-    const r: number = ((j + 1) >> 1) + len[j] - 1
+    const r: number = ((j + 1) >> 1) + radius[j] - 1
 
-    let L = r < q ? 0 : Math.min(r - q + 1, len[(j << 1) - i])
+    let L = r < q ? 0 : Math.min(r - q + 1, radius[(j << 1) - i])
     while (p > L - 1 && q + L < N && text[p - L] === text[q + L]) L += 1
-    len[i] = L
+    radius[i] = L
 
     // Update j
     if (q + L - 1 > r) j = i
   }
-  return len
+  return radius
 }
 
 export default manacher