feat: add recursion subsets (#5503)

This commit is contained in:
Tuhinm2002
2024-10-03 00:21:23 +05:30
committed by GitHub
parent e493eb2958
commit 013d122e7d
2 changed files with 72 additions and 0 deletions

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package com.thealgorithms.Recursion;
// program to find power set of a string
import java.util.ArrayList;
import java.util.List;
public final class GenerateSubsets {
private GenerateSubsets() {
throw new UnsupportedOperationException("Utility class");
}
public static List<String> subsetRecursion(String str) {
return doRecursion("", str);
}
private static List<String> doRecursion(String p, String up) {
if (up.isEmpty()) {
List<String> list = new ArrayList<>();
list.add(p);
return list;
}
// Taking the character
char ch = up.charAt(0);
// Adding the character in the recursion
List<String> left = doRecursion(p + ch, up.substring(1));
// Not adding the character in the recursion
List<String> right = doRecursion(p, up.substring(1));
left.addAll(right);
return left;
}
}

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package com.thealgorithms.Recursion;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import java.util.List;
import org.junit.jupiter.api.Test;
public final class GenerateSubsetsTest {
@Test
void subsetRecursionTestOne() {
String str = "abc";
String[] expected = new String[] {"abc", "ab", "ac", "a", "bc", "b", "c", ""};
List<String> ans = GenerateSubsets.subsetRecursion(str);
assertArrayEquals(ans.toArray(), expected);
}
@Test
void subsetRecursionTestTwo() {
String str = "cbf";
String[] expected = new String[] {"cbf", "cb", "cf", "c", "bf", "b", "f", ""};
List<String> ans = GenerateSubsets.subsetRecursion(str);
assertArrayEquals(ans.toArray(), expected);
}
@Test
void subsetRecursionTestThree() {
String str = "aba";
String[] expected = new String[] {"aba", "ab", "aa", "a", "ba", "b", "a", ""};
List<String> ans = GenerateSubsets.subsetRecursion(str);
assertArrayEquals(ans.toArray(), expected);
}
}