From 71640fcabc443a5e23f3dacbeebfcde64c0070c5 Mon Sep 17 00:00:00 2001 From: obvly Date: Tue, 31 Mar 2026 17:47:30 +0200 Subject: [PATCH 1/3] First Update --- .../java/practice/CandidateValidator.java | 15 ++++- src/main/java/practice/StreamPractice.java | 66 +++++++++++-------- 2 files changed, 53 insertions(+), 28 deletions(-) diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java index 8d2e56c0e..b85643809 100644 --- a/src/main/java/practice/CandidateValidator.java +++ b/src/main/java/practice/CandidateValidator.java @@ -1,5 +1,16 @@ package practice; -public class CandidateValidator { - //write your code here +import java.util.function.Predicate; +import model.Candidate; + +public class CandidateValidator implements Predicate { + @Override + public boolean test(Candidate candidate) { + String[] years = candidate.getPeriodsInUkr().split("-"); + int yearsInUkr = Integer.parseInt(years[1]) - Integer.parseInt(years[0]); + return candidate.getAge() >= 35 + && candidate.isAllowedToVote() + && "Ukrainian".equals(candidate.getNationality()) + && yearsInUkr >= 10; + } } diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 57b1ca2e2..d9ae66658 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -1,8 +1,13 @@ package practice; -import java.util.Collections; +import java.util.Arrays; +import java.util.Comparator; import java.util.List; +import java.util.NoSuchElementException; +import java.util.stream.Collectors; +import java.util.stream.IntStream; import model.Candidate; +import model.Cat; import model.Person; public class StreamPractice { @@ -14,7 +19,13 @@ public class StreamPractice { * "Can't get min value from list: < Here is our input 'numbers' >" */ public int findMinEvenNumber(List numbers) { - return 0; + return numbers.stream() + .flatMap(s -> Arrays.stream(s.split(","))) + .map(Integer::valueOf) + .filter(n -> n % 2 == 0) + .min(Comparator.naturalOrder()) + .orElseThrow(() -> new RuntimeException( + "Can't get min value from list: " + numbers)); } /** @@ -23,34 +34,36 @@ public int findMinEvenNumber(List numbers) { * But before that subtract 1 from each element on an odd position (having the odd index). */ public Double getOddNumsAverage(List numbers) { - return 0D; + return IntStream.range(0, numbers.size()) + .map(i -> i % 2 != 0 ? numbers.get(i) - 1 : numbers.get(i)) + .filter(n -> n % 2 != 0) + .average() + .orElseThrow(NoSuchElementException::new); } /** * Given a List of `Person` instances (having `name`, `age` and `sex` fields), - * for example, `Arrays.asList( new Person(«Victor», 16, Sex.MAN), - * new Person(«Helen», 42, Sex.WOMAN))`, * select from the List only men whose age is from `fromAge` to `toAge` inclusively. - *

- * Example: select men who can be recruited to army (from 18 to 27 years old inclusively). */ public List selectMenByAge(List peopleList, int fromAge, int toAge) { - return Collections.emptyList(); + return peopleList.stream() + .filter(p -> p.getSex() == Person.Sex.MAN) + .filter(p -> p.getAge() >= fromAge && p.getAge() <= toAge) + .collect(Collectors.toList()); } /** * Given a List of `Person` instances (having `name`, `age` and `sex` fields), - * for example, `Arrays.asList( new Person(«Victor», 16, Sex.MAN), - * new Person(«Helen», 42, Sex.WOMAN))`, * select from the List only people whose age is from `fromAge` and to `maleToAge` (for men) * or to `femaleToAge` (for women) inclusively. - *

- * Example: select people of working age - * (from 18 y.o. and to 60 y.o. for men and to 55 y.o. for women inclusively). */ public List getWorkablePeople(int fromAge, int femaleToAge, int maleToAge, List peopleList) { - return Collections.emptyList(); + return peopleList.stream() + .filter(p -> p.getAge() >= fromAge + && ((p.getSex() == Person.Sex.MAN && p.getAge() <= maleToAge) + || (p.getSex() == Person.Sex.WOMAN && p.getAge() <= femaleToAge))) + .collect(Collectors.toList()); } /** @@ -59,22 +72,23 @@ public List getWorkablePeople(int fromAge, int femaleToAge, * return the names of all cats whose owners are women from `femaleAge` years old inclusively. */ public List getCatsNames(List peopleList, int femaleAge) { - return Collections.emptyList(); + return peopleList.stream() + .filter(p -> p.getSex() == Person.Sex.WOMAN) + .filter(p -> p.getAge() >= femaleAge) + .flatMap(p -> p.getCats().stream()) + .map(Cat::getName) + .distinct() + .collect(Collectors.toList()); } /** - * Your help with a election is needed. Given list of candidates, where each element - * has Candidate.class type. - * Check which candidates are eligible to apply for president position and return their - * names sorted alphabetically. - * The requirements are: person should be older than 35 years, should be allowed to vote, - * have nationality - 'Ukrainian' - * and live in Ukraine for 10 years. For the last requirement use field periodsInUkr, - * which has following view: "2002-2015" - * We want to reuse our validation in future, so let's write our own impl of Predicate - * parametrized with Candidate in CandidateValidator. + * Your help with a election is needed. */ public List validateCandidates(List candidates) { - return Collections.emptyList(); + return candidates.stream() + .filter(new CandidateValidator()) + .map(Candidate::getName) + .sorted() + .collect(Collectors.toList()); } } From feb3f1b7306289fe86ea298dba685cbdfaf6317a Mon Sep 17 00:00:00 2001 From: obvly Date: Tue, 31 Mar 2026 17:51:42 +0200 Subject: [PATCH 2/3] Second Update --- .../java/practice/CandidateValidator.java | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java index b85643809..7ee73355b 100644 --- a/src/main/java/practice/CandidateValidator.java +++ b/src/main/java/practice/CandidateValidator.java @@ -4,13 +4,22 @@ import model.Candidate; public class CandidateValidator implements Predicate { + private static final int MIN_AGE = 35; + private static final int MIN_YEARS_IN_UKRAINE = 10; + private static final String REQUIRED_NATIONALITY = "Ukrainian"; + private static final String YEAR_SEPARATOR = "-"; + private static final int YEAR_FROM_INDEX = 0; + private static final int YEAR_TO_INDEX = 1; + @Override public boolean test(Candidate candidate) { - String[] years = candidate.getPeriodsInUkr().split("-"); - int yearsInUkr = Integer.parseInt(years[1]) - Integer.parseInt(years[0]); - return candidate.getAge() >= 35 + String[] years = candidate.getPeriodsInUkr().split(YEAR_SEPARATOR); + int yearsInUkr = Integer.parseInt(years[YEAR_TO_INDEX]) + - Integer.parseInt(years[YEAR_FROM_INDEX]); + + return candidate.getAge() >= MIN_AGE && candidate.isAllowedToVote() - && "Ukrainian".equals(candidate.getNationality()) - && yearsInUkr >= 10; + && REQUIRED_NATIONALITY.equals(candidate.getNationality()) + && yearsInUkr >= MIN_YEARS_IN_UKRAINE; } } From d6e063ad25f337baa413c87349b8d269b325f492 Mon Sep 17 00:00:00 2001 From: obvly Date: Tue, 31 Mar 2026 17:56:06 +0200 Subject: [PATCH 3/3] Delete .distinct --- src/main/java/practice/StreamPractice.java | 1 - 1 file changed, 1 deletion(-) diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index d9ae66658..5160d00c1 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -77,7 +77,6 @@ public List getCatsNames(List peopleList, int femaleAge) { .filter(p -> p.getAge() >= femaleAge) .flatMap(p -> p.getCats().stream()) .map(Cat::getName) - .distinct() .collect(Collectors.toList()); }