5. Longest Palindromic Substring Go语言

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000.
Example 1:
Input: “babad”
Output: “bab”
Note: “aba” is also a valid answer.
Example 2:
Input: “cbbd”
Output: “bb”

思路：
最长的回文字符串的长度可能是奇数也可能是偶数。则分两种情况考虑,
（1）针对奇数情况，则从当前字符的前后两个字符开始比较
（2）针对偶数情况，则从当前字符与其后一个字符开始比较

package main

import "fmt"

func main()  {
	s := "cbbd"
	ret := longestPalindrome(s)
	fmt.Println(ret)

}

func longestPalindrome(s string) string {
	if (len(s) < 2){
		return s
	}
	result := string(s[0])
	for i := 0; i < len(s); i++ {
		ret := getPalindrome(s, i, i)   // 处理奇数情况
		if (len(ret) > len(result)){
			result = ret
		}
		ret = getPalindrome(s, i, i + 1)  // 处理偶数情况
		if (len(ret) > len(result)){
			result = ret
		}
	}
	return result
}

func getPalindrome(s string, beg int, end int) string {
	for {
		if ((beg >= 0) && (end < len(s) && (s[beg] == s[end]))){
			beg--
			end++
		}else {
			break
		}
	}
	beg++
	return s[beg : end]
}