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49 | class Solution {
private:
string expandOdd(int idx, string& s) {
int i = 1;
for (; i < s.size(); i++) {
if (idx - i < 0)
break;
if (idx + i >= s.size())
break;
if (s[idx - i] != s[idx + i])
break;
}
i--;
int left = idx - i;
int len = i * 2 + 1;
return s.substr(left, len);
}
string expandEven(int idx, string& s) {
int i = 1;
for (; i < s.size(); i++) {
if (idx - i + 1 < 0)
break;
if (idx + i >= s.size())
break;
if (s[idx - i + 1] != s[idx + i])
break;
}
i--;
int left = idx - i + 1;
int len = i * 2;
return s.substr(left, len);
}
public:
string longestPalindrome(string s) {
string ansStr = "";
for (int i = 0; i < s.size(); i++) {
string oddStr = expandOdd(i, s);
if (oddStr.size() > ansStr.size())
ansStr = oddStr;
string evenStr = expandEven(i, s);
if (evenStr.size() > ansStr.size())
ansStr = evenStr;
}
return ansStr;
}
};
|