diff --git a/problems/0844.比较含退格的字符串.md b/problems/0844.比较含退格的字符串.md index 5d629a8c..00d52e42 100644 --- a/problems/0844.比较含退格的字符串.md +++ b/problems/0844.比较含退格的字符串.md @@ -205,6 +205,42 @@ class Solution: return self.get_string(s) == self.get_string(t) pass ``` +双指针 +```python +class Solution: + def backspaceCompare(self, s: str, t: str) -> bool: + s_index, t_index = len(s) - 1, len(t) - 1 + s_backspace, t_backspace = 0, 0 # 记录s,t的#数量 + while s_index >= 0 or t_index >= 0: # 使用or,以防长度不一致 + while s_index >= 0: # 从后向前,消除s的# + if s[s_index] == '#': + s_index -= 1 + s_backspace += 1 + else: + if s_backspace > 0: + s_index -= 1 + s_backspace -= 1 + else: + break + while t_index >= 0: # 从后向前,消除t的# + if t[t_index] == '#': + t_index -= 1 + t_backspace += 1 + else: + if t_backspace > 0: + t_index -= 1 + t_backspace -= 1 + else: + break + if s_index >= 0 and t_index >= 0: # 后半部分#消除完了,接下来比较当前位的值 + if s[s_index] != t[t_index]: + return False + elif s_index >= 0 or t_index >= 0: # 一个字符串找到了待比较的字符,另一个没有,返回False + return False + s_index -= 1 + t_index -= 1 + return True +``` ### Go @@ -226,6 +262,51 @@ func backspaceCompare(s string, t string) bool { return getString(s) == getString(t) } +``` +双指针 +```go +func backspaceCompare(s string, t string) bool { + s_index, t_index := len(s) - 1, len(t) - 1 + s_backspace, t_backspace := 0, 0 // 记录s,t的#数量 + for s_index >= 0 || t_index >= 0 { // 使用or,以防长度不一致 + for s_index >= 0 { // 从后向前,消除s的# + if s[s_index] == '#' { + s_index-- + s_backspace++ + } else { + if s_backspace > 0 { + s_index-- + s_backspace-- + } else { + break + } + } + } + for t_index >= 0 { // 从后向前,消除t的# + if t[t_index] == '#' { + t_index-- + t_backspace++ + } else { + if t_backspace > 0 { + t_index-- + t_backspace-- + } else { + break + } + } + } + if s_index >= 0 && t_index >= 0 { // 后半部分#消除完了,接下来比较当前位的值 + if s[s_index] != t[t_index] { + return false + } + } else if s_index >= 0 || t_index >= 0 { // 一个字符串找到了待比较的字符,另一个没有,返回false + return false + } + s_index-- + t_index-- + } + return true +} ``` ### JavaScript diff --git a/problems/剑指Offer58-II.左旋转字符串.md b/problems/剑指Offer58-II.左旋转字符串.md index c391d661..61391274 100644 --- a/problems/剑指Offer58-II.左旋转字符串.md +++ b/problems/剑指Offer58-II.左旋转字符串.md @@ -209,6 +209,61 @@ var reverseLeftWords = function(s, n) { }; ``` +版本二(在原字符串上操作): + +```js +/** + * @param {string} s + * @param {number} n + * @return {string} + */ +var reverseLeftWords = function (s, n) { + /** Utils */ + function reverseWords(strArr, start, end) { + let temp; + while (start < end) { + temp = strArr[start]; + strArr[start] = strArr[end]; + strArr[end] = temp; + start++; + end--; + } + } + /** Main code */ + let strArr = s.split(''); + let length = strArr.length; + reverseWords(strArr, 0, length - 1); + reverseWords(strArr, 0, length - n - 1); + reverseWords(strArr, length - n, length - 1); + return strArr.join(''); +}; +``` + +TypeScript: + +```typescript +function reverseLeftWords(s: string, n: number): string { + /** Utils */ + function reverseWords(strArr: string[], start: number, end: number): void { + let temp: string; + while (start < end) { + temp = strArr[start]; + strArr[start] = strArr[end]; + strArr[end] = temp; + start++; + end--; + } + } + /** Main code */ + let strArr: string[] = s.split(''); + let length: number = strArr.length; + reverseWords(strArr, 0, length - 1); + reverseWords(strArr, 0, length - n - 1); + reverseWords(strArr, length - n, length - 1); + return strArr.join(''); +}; +``` + Swift: ```swift