给定一个字符串,计算该字符串的最长回文子串。
方法1:
枚举所有子串,逐一判断各个子串是否是回文。
/*
*Created on 2015年12月23日
*Copyright 2015 Yong Cai Limited crop. All Rights Reserved
*
*/
public class LongestPalindrome{
public static void main(String[] args) {
String input = "ceuvhiwfw 6412345678900009876543212841upwsv,";
System.out.println(CollectionShuffle.compute(input));
}
public static String compute(String input) {
char[] inputArray = input.toCharArray();
int len = inputArray.length;
int finalStart = 0, finalEnd = 0, finalLength = 0;
//从长到短生成子串
for (int i = 0; i < len; i++) {
for (int start = 0, end = len - i - 1; end < len; start++, end++) {
//对每一个子串,判断是否是回文
for (int m = start, k = end; m <= k; m++, k--) {
if (inputArray[m] != inputArray[k]) {
break;
} else {
if (m == k || m == (k - 1)) {
if ((end - start) > finalLength) {
finalStart = start;
finalEnd = end;
finalLength = end - start;
//后面生成的子串长度小于已经求得最长回文长度,则可以终止计算
if (finalLength > (end - start)) {
return input.substring(finalStart,
finalEnd + 1);
}
}
}
}
}
}
}
return input.substring(finalStart, finalEnd + 1);
}
}
输入1:ceuvhiwfw 6412345678900009876543212841upwsv,
输出1:1234567890000987654321
输入2:cuhfqwertyuiopoiuytrewqieuhf
输出2:qwertyuiopoiuytrewq