Merge pull request #526 from kok-s0s/master

提供字符串部分的JavaScript代码

problems/0028.实现strStr.md

@@ -808,7 +808,93 @@ func strStr(haystack string, needle string) int {
 }
 ```
 
+JavaScript版本
 
+> 前缀表统一减一
+
+```javascript
+/**
+ * @param {string} haystack
+ * @param {string} needle
+ * @return {number}
+ */
+var strStr = function (haystack, needle) {
+    if (needle.length === 0)
+        return 0;
+
+    const getNext = (needle) => {
+        let next = [];
+        let j = -1;
+        next.push(j);
+
+        for (let i = 1; i < needle.length; ++i) {
+            while (j >= 0 && needle[i] !== needle[j + 1])
+                j = next[j];
+            if (needle[i] === needle[j + 1])
+                j++;
+            next.push(j);
+        }
+
+        return next;
+    }
+
+    let next = getNext(needle);
+    let j = -1;
+    for (let i = 0; i < haystack.length; ++i) {
+        while (j >= 0 && haystack[i] !== needle[j + 1])
+            j = next[j];
+        if (haystack[i] === needle[j + 1])
+            j++;
+        if (j === needle.length - 1)
+            return (i - needle.length + 1);
+    }
+
+    return -1;
+};
+```
+
+> 前缀表统一不减一
+
+```javascript
+/**
+ * @param {string} haystack
+ * @param {string} needle
+ * @return {number}
+ */
+var strStr = function (haystack, needle) {
+    if (needle.length === 0)
+        return 0;
+
+    const getNext = (needle) => {
+        let next = [];
+        let j = 0;
+        next.push(j);
+
+        for (let i = 1; i < needle.length; ++i) {
+            while (j > 0 && needle[i] !== needle[j])
+                j = next[j - 1];
+            if (needle[i] === needle[j])
+                j++;
+            next.push(j);
+        }
+
+        return next;
+    }
+
+    let next = getNext(needle);
+    let j = 0;
+    for (let i = 0; i < haystack.length; ++i) {
+        while (j > 0 && haystack[i] !== needle[j])
+            j = next[j - 1];
+        if (haystack[i] === needle[j])
+            j++;
+        if (j === needle.length)
+            return (i - needle.length + 1);
+    }
+
+    return -1;
+};
+```
 
 
 

problems/0459.重复的子字符串.md

@@ -289,8 +289,79 @@ func repeatedSubstringPattern(s string) bool {
 }
 ```
 
+JavaScript版本
 
+> 前缀表统一减一
 
+```javascript
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var repeatedSubstringPattern = function (s) {
+    if (s.length === 0)
+        return false;
+
+    const getNext = (s) => {
+        let next = [];
+        let j = -1;
+
+        next.push(j);
+
+        for (let i = 1; i < s.length; ++i) {
+            while (j >= 0 && s[i] !== s[j + 1])
+                j = next[j];
+            if (s[i] === s[j + 1])
+                j++;
+            next.push(j);
+        }
+
+        return next;
+    }
+
+    let next = getNext(s);
+
+    if (next[next.length - 1] !== -1 && s.length % (s.length - (next[next.length - 1] + 1)) === 0)
+        return true;
+    return false;
+};
+```
+
+> 前缀表统一不减一
+
+```javascript
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var repeatedSubstringPattern = function (s) {
+    if (s.length === 0)
+        return false;
+
+    const getNext = (s) => {
+        let next = [];
+        let j = 0;
+
+        next.push(j);
+
+        for (let i = 1; i < s.length; ++i) {
+            while (j > 0 && s[i] !== s[j])
+                j = next[j - 1];
+            if (s[i] === s[j])
+                j++;
+            next.push(j);
+        }
+
+        return next;
+    }
+
+    let next = getNext(s);
+
+    if (next[next.length - 1] !== 0 && s.length % (s.length - next[next.length - 1]) === 0)
+        return true;
+    return false;
+};
+```
 
 
 

problems/剑指Offer58-II.左旋转字符串.md

@@ -165,41 +165,26 @@ func reverse(b []byte, left, right int){
 ```
 
 
-javaScript:
+JavaScript：
 
-```js
-/**
- * @param {string} s
- * @param {number} n
- * @return {string}
- */
+```javascript
 var reverseLeftWords = function (s, n) {
-  const strArr = Array.from(s);
-  reverse(strArr, 0, n - 1);
-  reverse(strArr, n, strArr.length - 1);
-  reverse(strArr, 0, strArr.length - 1);
-  return strArr.join('');
-};
-
-// 翻转从 start 到 end 的字符
-function reverse(strArr, start, end) {
-  let left = start;
-  let right = end;
-
-  while(left < right) {
-    // 交换
+    const reverse = (str, left, right) => {
+        let strArr = str.split("");
+        for (; left < right; left++, right--) {
             [strArr[left], strArr[right]] = [strArr[right], strArr[left]];
-    left++;
-    right--;
         }
+        return strArr.join("");
     }
+    s = reverse(s, 0, n - 1);
+    s = reverse(s, n, s.length - 1);
+    return reverse(s, 0, s.length - 1);
+};
 ```
 
 
 
 
-
-
 -----------------------
 * 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
 * B站视频：[代码随想录](https://space.bilibili.com/525438321)