public class LongestSubstringMatch {
public static void main(String[] args) {
// Test cases
String text1 = "hackerrank";
String regex1 = "ack*r";
System.out.println(getLongestMatch(text1, regex1)); // Output: 6
String text2 = "programming";
String regex2 = "r*in";
System.out.println(getLongestMatch(text2, regex2)); // Output: 6
String text3 = "debug";
String regex3 = "ug*eb";
System.out.println(getLongestMatch(text3, regex3)); // Output: -1
}
// public static int getLongestMatch(String text, String regex) {
// // Split the regex into parts before and after the wildcard character '*'
// String[] parts = regex.split("\\*");
// if (parts.length != 2) {
// return -1; // Invalid regex format
// }
// String prefix = parts[0];
// String suffix = parts[1];
// int maxLen = -1;
// // Traverse through the text and find substrings that match the regex
// for (int i = 0; i <= text.length() - prefix.length(); i++) {
// if (text.startsWith(prefix, i)) {
// for (int j = i + prefix.length(); j <= text.length(); j++) {
// if (text.startsWith(suffix, j)) {
// maxLen = Math.max(maxLen, j - i + suffix.length());
// }
// }
// }
// }
// return maxLen;
// }
public static int getLongestMatch(String text, String regex) {
String[] parts = regex.split("\\*");
if (parts.length != 2) {
return -1;
}
String prefix = parts[0];
String suffix = parts[1];
int maxLen = -1;
int prefixLen = prefix.length();
int suffixLen = suffix.length();
int textLen = text.length();
int prefixIndex = 0;
int suffixIndex = textLen - suffixLen;
while (prefixIndex <= textLen - prefixLen) {
if (text.startsWith(prefix, prefixIndex)) {
while (suffixIndex >= prefixIndex + prefixLen) {
if (text.startsWith(suffix, suffixIndex)) {
int currentMatchLength = suffixIndex + suffixLen - prefixIndex;
maxLen = Math.max(maxLen, currentMatchLength);
break; // Found a suffix, no need to check further
}
suffixIndex--;
}
suffixIndex = textLen - suffixLen;
}
prefixIndex++;
}
return maxLen;
}
}
