leetcode讲解--917. Reverse Only Letters

题目Given a string S, return the “reversed” string where all characters that are not a letter stay in the same place, and all letters reverse their positions.Example 1:Input: “ab-cd"Output: “dc-ba"Example 2:Input: “a-bC-dEf-ghIj"Output: “j-Ih-gfE-dCba"Example 3:Input: “Test1ng-Leet=code-Q!“Output: “Qedo1ct-eeLg=ntse-T!“Note:S.length <= 10033 <= S[i].ASCIIcode <= 122S doesn’t contain \ or “讲解字符串操作，将字母reverse，其他字符保持在原来位置上。我使用了两个数组，一个指针java代码class Solution { public String reverseOnlyLetters(String S) { char[] c = S.toCharArray(); char[] result = S.toCharArray(); int index = result.length-1; for(int i=0;i<c.length;i++){ if(c[i]>=‘a’ && c[i]<=‘z’ || c[i]>=‘A’ && c[i]<=‘Z’){ while(index>=0 && !(result[index]>=‘a’ && result[index]<=‘z’ || result[index]>=‘A’ && result[index]<=‘Z’)){ index–; } if(index>=0) result[index–] = c[i]; } } return String.valueOf(result); }}