JavaAlgorithms/Strings/LongestPalindromicSubstring.java
2021-10-16 16:43:51 +03:00

46 lines
1.2 KiB
Java

package Strings;
// Longest Palindromic Substring
import java.util.Scanner;;
class LongestPalindromicSubstring {
public static void main(String[] args) {
Solution s = new Solution();
String str = "";
Scanner sc = new Scanner(System.in);
System.out.print("Enter the string: ");
str = sc.nextLine();
System.out.println("Longest substring is : "+s.longestPalindrome(str));
}
}
class Solution {
public String longestPalindrome(String s) {
if (s == null || s.length() == 0) {
return "";
}
int n = s.length();
String maxStr = "";
for (int i = 0; i < n; ++i) {
for (int j = i; j < n; ++j) {
if (isValid(s, i, j) == true) {
if (j - i + 1 > maxStr.length()) { // update maxStr
maxStr = s.substring(i, j + 1);
}
}
}
}
return maxStr;
}
private boolean isValid(String s, int lo, int hi) {
int n = hi - lo + 1;
for (int i = 0; i < n / 2; ++i) {
if (s.charAt(lo + i) != s.charAt(hi - i)) {
return false;
}
}
return true;
}
}