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This commit is related to BAEL-7722 (#16382) 

This commit aims to update SymmetricSubstringMaxLengthUnitTest.java.
This commit is contained in:
Mo Helmy 2024-04-11 22:37:39 +02:00 committed by GitHub
parent 1c569bcafc
commit ae5290fe76
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1 changed files with 50 additions and 53 deletions
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103
core-java-modules/core-java-string-operations-8/src/test/java/com/baeldung/symmetricsubstringlength/SymmetricSubstringMaxLengthUnitTest.java
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@ -5,73 +5,70 @@ import org.junit.Test;
import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertEquals;
public class SymmetricSubstringMaxLengthUnitTest { public class SymmetricSubstringMaxLengthUnitTest {
String input = "<><??>>"; String input = "abba";
int expected = 4; int expected = 4;
@Test static int findLongestSymmetricSubstringUsingSymmetricApproach(String str) {
public void givenString_whenUsingSymmetricSubstringExpansion_thenFindLongestSymmetricSubstring() { int maxLength = 1;
int start = 0;
int mid = 0;
int last_gt = 0;
int end = 0;
int best = 0;
while (start < input.length()) { for (int i = 0; i < str.length(); i++) {
int current = Math.min(mid - start, end - mid); for (int j = i; j < str.length(); j++) {
if (best < current) { int flag = 1;
best = current; for (int k = 0; k < (j - i + 1) / 2; k++) {
} if (str.charAt(i + k) != str.charAt(j - k)) {
flag = 0;
if (end - mid == current && end < input.length()) { break;
if (input.charAt(end) == '?') { }
end++; }
} else if (input.charAt(end) == '>') { if (flag != 0 && (j - i + 1) > maxLength) {
end++; maxLength = j - i + 1;
last_gt = end;
} else {
end++;
mid = end;
start = Math.max(start, last_gt);
} }
} else if (mid < input.length() && input.charAt(mid) == '?') {
mid++;
} else if (start < mid) {
start++;
} else {
start = Math.max(start, last_gt);
mid++;
end = Math.max(mid, end);
} }
} }
int result = 2 * best; return maxLength;
assertEquals(expected, result);
} }
@Test @Test
public void givenString_whenUsingBruteForce_thenFindLongestSymmetricSubstring() { public void givenString_whenUsingBruteForce_thenFindLongestSymmetricSubstring() {
int max = 0; assertEquals(expected, findLongestSymmetricSubstringUsingBruteForce(input).length());
for (int i = 0; i < input.length(); i++) { }
for (int j = i + 1; j <= input.length(); j++) {
String t = input.substring(i, j); @Test
if (t.length() % 2 == 0) { public void givenString_whenUsingSymmetricSubstring_thenFindLongestSymmetricSubstring() {
int k = 0, l = t.length() - 1; assertEquals(expected, findLongestSymmetricSubstringUsingSymmetricApproach(input));
boolean isSym = true; }
while (k < l && isSym) {
if (!(t.charAt(k) == '<' || t.charAt(k) == '?') && (t.charAt(l) == '>' || t.charAt(l) == '?')) { private String findLongestSymmetricSubstringUsingBruteForce(String str) {
isSym = false; if (str == null || str.length() == 0) {
} return "";
k++; }
l--;
} int maxLength = 0;
if (isSym) { String longestPalindrome = "";
max = Math.max(max, t.length());
} for (int i = 0; i < str.length(); i++) {
for (int j = i + 1; j <= str.length(); j++) {
String substring = str.substring(i, j);
if (isPalindrome(substring) && substring.length() > maxLength) {
maxLength = substring.length();
longestPalindrome = substring;
} }
} }
} }
assertEquals(expected, max); return longestPalindrome;
} }
private boolean isPalindrome(String s) {
int left = 0;
int right = s.length() - 1;
while (left < right) {
if (s.charAt(left) != s.charAt(right)) {
return false;
}
left++;
right--;
}
return true;
}
} }