/**
- Write a program to "factorize" the extremities of two ASCII strings {@code str1} and {@code str2}.
-
- Your must return a single string, initially made from the concatenation of two given strings.
- The longest substrings that is common between the end of the first string and the beginning
- of the second one must be factorized (written only once).
-
- You must decide the concatenation order {@code str1 + str2} or {@code str2 + str1} so that
- you get the best factorization.
-
- When the same number characters can be factorized by the two concatenation
- orders, prioritize {@code str1 + str2}.
-
-
Detailed example
- With these parameters:
-
-
<li>{@code str1 = "1234yyabc"}</li> -
<li>{@code str2 = "abcxxxx1234"}</li>
-
- If you choose the order {@code str1 + str2} you could factorize the substring {@code "abc"}. Then,
- you would return {@code "abcxxxx1234yyabc"}.
*/
public class Factorize {
public static int redundant(String first, String second) {
for (int idx = second.length() - 1; idx >= 0; idx--) {
String sub = second.substring(0, idx);
if (first.endsWith(sub)) {
return sub.length();
}
}
return 0;
}
/**
* @param str1 The first ASCII string to factorize.
* @param str2 The second ASCII string to factorize.
* @return The result string, after concatenation and factorization.
*/
public static String factorizeExtremities(String str1, String str2) {
if (str1.equals(str2)) {
return str1;
}
int firstOcc = redundant(str1, str2);
int secondOcc = redundant(str2, str1);
if (secondOcc > firstOcc) {
return str2.concat(str1.substring(secondOcc));
}
return str1.concat(str2.substring(firstOcc));
}
public static void main(String[] args) {
System.out.println("Using example: " + factorizeExtremities("1234yyabc", "abcxxxx1234"));
System.out.println("Using example: " + factorizeExtremities("UUUUUUUUUUUUUU", "UUUUU"));
}}
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