5. Longest Palindromic Substring
123456789101112131415161718192021222324252627282930313233343536
// Given a center, either one letter or two letter,
// Find longest palindrome
var getPalindromeSubstring = function(s, i, j) {
while (i >= 0 && j < s.length && s[i] === s[j]) {
i--;
j++;
}
return s.substring(i + 1, j);
};
var longestPalindrome = function(s) {
if (!s) return s;
var longest = s.substring(0, 1);
for (var i = 0; i < s.length; i++) {
// odd
var tmp = getPalindromeSubstring(s, i, i);
if (tmp.length > longest.length) {
longest = tmp;
}
//console.log('-----',s,i,i,tmp);
// even, get longest palindrome with center of i, i+1
tmp = getPalindromeSubstring(s, i, i + 1);
if (tmp.length > longest.length) {
longest = tmp;
}
//console.log('######',s,i,i+1,tmp);
}
return longest;
};
console.log(longestPalindrome("aacabdkacaa"));
JavaScript
INFO