5. 最长回文子串
题目
代码
class Solution {
public:
string longestPalindrome(string s) {
if(s.size()==1)
return s;
string max=s.substr(0,1);
int maxLength=0;
for(int i=0;i<s.size();i++)
{
int step=0;
//偶数对称型
while((i+step+1)<s.size()&&(i-step)>=0&&s[i+step+1]==s[i-step])
step++;
if(step>0&&(2*step)>maxLength)
{
maxLength=2*step;
max=s.substr(i-step+1,step*2);
}
//奇数对称型
step=1;
while((i-step)>=0&&(i+step)<s.size()&&s[i-step]==s[i+step])
step++;
if(step>1&&(2*step-1)>maxLength)
{
maxLength=2*step-1;
max=s.substr(i-step+1,step*2-1);
}
}
return max;
}
};
https://github.com/li-zheng-hao