本文共 1085 字,大约阅读时间需要 3 分钟。
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
For example,
"A man, a plan, a canal: Panama"
is a palindrome.
"race a car"
is not a palindrome.
Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.
For the purpose of this problem, we define empty string as valid palindrome.
需要注意点:
1)empty string问题(不能用while(!chacter[left]) left++)而要用if(!chacter[left]){left++ continue}
2)大小写字母的转换,注意0~9系统是认识的。
class Solution {
public: bool isCharacter(char c) { if((c >= 'a'&&c <= 'z')||(c >= 'A' && c <= 'Z')||(c >= '0'&&c <= '9')) return true; else return false; } char Turntosmallalpha(char c) { if(c >= 'A'&&c <= 'Z') c = c + 'a' - 'A'; return c; } bool isPalindrome(string s) { int left = 0; int right = s.size() - 1; bool flg = true; while(left <= right) { if(!isCharacter(s[left])) { left ++; continue; } if(!isCharacter(s[right])) { right --; continue; } if(Turntosmallalpha(s[left]) != Turntosmallalpha(s[right])) { flg = false; break; } left ++; right --; } return flg; } };转载地址:http://bpbci.baihongyu.com/