🌵5. Longest Palindromic Substring
https://leetcode.com/problems/longest-palindromic-substring/
js
/**
* @param {string} s
* @return {string}
*/
var longestPalindrome = function(s) {
var start = 0
var end = 0
for (let i = 0; i < s.length; i++) {
let len1 = expandAroundCenter(s, i, i)
let len2 = expandAroundCenter(s, i, i + 1)
let len = Math.max(len1, len2)
if (len > end - start) {
start = i - ((len - 1) / 2 >> 0)
end = i + (len / 2 >> 0)
}
}
return s.substring(start, end + 1)
}
function expandAroundCenter(s, left, right) {
while (left >= 0 && right < s.length && s[left] == s[right]) {
left--
right++
}
return right - left - 1
}py
class Solution(object):
def longestPalindrome(self, s):
"""
:type s: str
:rtype: str
"""
start, end = 0, 0
for i in range(len(s)):
len1 = self.expandAroundCenter(s, i, i)
len2 = self.expandAroundCenter(s, i, i + 1)
length = max(len1, len2)
if length > end - start:
start = i - (length - 1) // 2
end = i + length // 2
return s[start:end + 1]
def expandAroundCenter(self, s, left, right):
while left >= 0 and right < len(s) and s[left] == s[right]:
left -= 1
right += 1
return right - left - 1go
func longestPalindrome(s string) string {
start, end := 0, 0
for i := 0; i < len(s); i++ {
len1 := expandAroundCenter(s, i, i)
len2 := expandAroundCenter(s, i, i+1)
length := max(len1, len2)
if length > end-start {
start = i - (length-1)/2
end = i + length/2
}
}
return s[start : end+1]
}
func expandAroundCenter(s string, left int, right int) int {
for left >= 0 && right < len(s) && s[left] == s[right] {
left--
right++
}
return right - left - 1
}
func max(x int, y int) int {
if x >= y {
return x
}
return y
}