From f1761e0f644a3fc79604f9354eee3db185813c8e Mon Sep 17 00:00:00 2001 From: Evhenii Shylov Date: Mon, 25 May 2026 13:14:32 +0300 Subject: [PATCH 1/3] first-attempt --- .../java/practice/CandidateValidator.java | 16 ++++- src/main/java/practice/StreamPractice.java | 65 +++++++++++++++++-- 2 files changed, 74 insertions(+), 7 deletions(-) diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java index 8d2e56c0e..d856693a5 100644 --- a/src/main/java/practice/CandidateValidator.java +++ b/src/main/java/practice/CandidateValidator.java @@ -1,5 +1,19 @@ package practice; -public class CandidateValidator { +import java.util.function.Predicate; +import model.Candidate; + +public class CandidateValidator implements Predicate { + @Override + public boolean test(Candidate candidate) { + if (candidate.getAge() < 35 || !candidate.isAllowedToVote() + || !"Ukrainian".equals(candidate.getNationality())) { + return false; + } + String[] years = candidate.getPeriodsInUkr().split("-"); + int yearsInUkraine = Integer.parseInt(years[1]) - Integer.parseInt(years[0]); + + return yearsInUkraine >= 10; + } //write your code here } diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 57b1ca2e2..46c4e0c6f 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -1,8 +1,12 @@ package practice; +import java.util.Arrays; import java.util.Collections; import java.util.List; +import java.util.NoSuchElementException; +import java.util.stream.Collectors; import model.Candidate; +import model.Cat; import model.Person; public class StreamPractice { @@ -14,7 +18,16 @@ public class StreamPractice { * "Can't get min value from list: < Here is our input 'numbers' >" */ public int findMinEvenNumber(List numbers) { - return 0; + if (numbers == null || numbers.isEmpty()) { + throw new RuntimeException("Can't get min value from list: " + numbers); + } + return numbers.stream() + .flatMap(s -> Arrays.stream(s.split(","))) + .mapToInt(Integer::parseInt) + .filter(n -> n % 2 == 0) + .min() + .orElseThrow(() -> + new RuntimeException("Can`t get min value from list: " + numbers)); } /** @@ -23,7 +36,18 @@ 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; + if (numbers == null || numbers.isEmpty()) { + throw new NoSuchElementException("List is empty or null from list: " + numbers); + } + for (int i = 1; i < numbers.size(); i += 2) { + numbers.set(i, numbers.get(i) - 1); + } + return numbers.stream() + .mapToInt(Integer::intValue) + .filter(n -> n % 2 != 0) + .average() + .orElseThrow(() -> + new NoSuchElementException("No odd numbers found from list: " + numbers)); } /** @@ -35,7 +59,13 @@ public Double getOddNumsAverage(List numbers) { * 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(); + if (peopleList == null || peopleList.isEmpty()) { + return Collections.emptyList(); + } + return peopleList.stream() + .filter(p -> p.getSex() == Person.Sex.MAN) + .filter(p -> p.getAge() >= fromAge && p.getAge() <= toAge) + .collect(Collectors.toList()); } /** @@ -50,7 +80,14 @@ public List selectMenByAge(List peopleList, int fromAge, int toA */ public List getWorkablePeople(int fromAge, int femaleToAge, int maleToAge, List peopleList) { - return Collections.emptyList(); + if (peopleList == null || peopleList.isEmpty()) { + return Collections.emptyList(); + } + return peopleList.stream() + .filter(p -> p.getAge() >= fromAge) + .filter(p -> p.getAge() <= maleToAge && p.getSex() == Person.Sex.MAN + || p.getAge() <= femaleToAge && p.getSex() == Person.Sex.WOMAN) + .collect(Collectors.toList()); } /** @@ -59,7 +96,15 @@ 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(); + if (peopleList == null || peopleList.isEmpty()) { + return Collections.emptyList(); + } + return peopleList.stream() + .filter(p -> p.getAge() > femaleAge && p.getSex() == Person.Sex.WOMAN) + .filter(p -> p.getCats() != null) + .flatMap(p -> p.getCats().stream()) + .map(Cat::getName) + .collect(Collectors.toList()); } /** @@ -75,6 +120,14 @@ public List getCatsNames(List peopleList, int femaleAge) { * parametrized with Candidate in CandidateValidator. */ public List validateCandidates(List candidates) { - return Collections.emptyList(); + if (candidates == null || candidates.isEmpty()) { + return Collections.emptyList(); + } + CandidateValidator validator = new CandidateValidator(); + return candidates.stream() + .filter(validator) + .map(Candidate::getName) + .sorted() + .collect(Collectors.toList()); } } From d16f200525965d3ac740a30665750117cd9bbb68 Mon Sep 17 00:00:00 2001 From: Evhenii Shylov Date: Mon, 25 May 2026 13:37:03 +0300 Subject: [PATCH 2/3] second-attempt --- .../java/practice/CandidateValidator.java | 23 ++++++++++++++----- src/main/java/practice/StreamPractice.java | 16 ++++++------- 2 files changed, 24 insertions(+), 15 deletions(-) diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java index d856693a5..04a8a6c68 100644 --- a/src/main/java/practice/CandidateValidator.java +++ b/src/main/java/practice/CandidateValidator.java @@ -4,16 +4,27 @@ 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 START_YEAR_INDEX = 0; + private static final int END_YEAR_INDEX = 1; + @Override public boolean test(Candidate candidate) { - if (candidate.getAge() < 35 || !candidate.isAllowedToVote() - || !"Ukrainian".equals(candidate.getNationality())) { + if (candidate == null) { return false; } - String[] years = candidate.getPeriodsInUkr().split("-"); - int yearsInUkraine = Integer.parseInt(years[1]) - Integer.parseInt(years[0]); - return yearsInUkraine >= 10; + if (candidate.getAge() < MIN_AGE + || !candidate.isAllowedToVote() + || !REQUIRED_NATIONALITY.equals(candidate.getNationality())) { + return false; + } + String[] years = candidate.getPeriodsInUkr().split(YEAR_SEPARATOR); + int yearsInUkr = Integer.parseInt(years[END_YEAR_INDEX]) + - Integer.parseInt(years[START_YEAR_INDEX]); + return yearsInUkr >= MIN_YEARS_IN_UKRAINE; } - //write your code here } diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 46c4e0c6f..05376bd26 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -5,6 +5,7 @@ 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; @@ -27,7 +28,7 @@ public int findMinEvenNumber(List numbers) { .filter(n -> n % 2 == 0) .min() .orElseThrow(() -> - new RuntimeException("Can`t get min value from list: " + numbers)); + new RuntimeException("Can't get min value from list: " + numbers)); } /** @@ -39,11 +40,8 @@ public Double getOddNumsAverage(List numbers) { if (numbers == null || numbers.isEmpty()) { throw new NoSuchElementException("List is empty or null from list: " + numbers); } - for (int i = 1; i < numbers.size(); i += 2) { - numbers.set(i, numbers.get(i) - 1); - } - return numbers.stream() - .mapToInt(Integer::intValue) + 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(() -> @@ -85,8 +83,8 @@ public List getWorkablePeople(int fromAge, int femaleToAge, } return peopleList.stream() .filter(p -> p.getAge() >= fromAge) - .filter(p -> p.getAge() <= maleToAge && p.getSex() == Person.Sex.MAN - || p.getAge() <= femaleToAge && p.getSex() == Person.Sex.WOMAN) + .filter(p -> p.getAge() <= maleToAge && Person.Sex.MAN.equals(p.getSex()) + || p.getAge() <= femaleToAge && p.getSex().equals(Person.Sex.WOMAN)) .collect(Collectors.toList()); } @@ -100,7 +98,7 @@ public List getCatsNames(List peopleList, int femaleAge) { return Collections.emptyList(); } return peopleList.stream() - .filter(p -> p.getAge() > femaleAge && p.getSex() == Person.Sex.WOMAN) + .filter(p -> p.getAge() >= femaleAge && p.getSex().equals(Person.Sex.WOMAN)) .filter(p -> p.getCats() != null) .flatMap(p -> p.getCats().stream()) .map(Cat::getName) From 20016b4547aa4d1e839955518c15ab2cfbe0deb4 Mon Sep 17 00:00:00 2001 From: Evhenii Shylov Date: Mon, 25 May 2026 15:09:08 +0300 Subject: [PATCH 3/3] third-attempt --- src/main/java/practice/StreamPractice.java | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 05376bd26..1b60ce2bf 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -61,7 +61,7 @@ public List selectMenByAge(List peopleList, int fromAge, int toA return Collections.emptyList(); } return peopleList.stream() - .filter(p -> p.getSex() == Person.Sex.MAN) + .filter(p -> p.getSex().equals(Person.Sex.MAN)) .filter(p -> p.getAge() >= fromAge && p.getAge() <= toAge) .collect(Collectors.toList()); } @@ -83,7 +83,7 @@ public List getWorkablePeople(int fromAge, int femaleToAge, } return peopleList.stream() .filter(p -> p.getAge() >= fromAge) - .filter(p -> p.getAge() <= maleToAge && Person.Sex.MAN.equals(p.getSex()) + .filter(p -> p.getAge() <= maleToAge && p.getSex().equals(Person.Sex.MAN) || p.getAge() <= femaleToAge && p.getSex().equals(Person.Sex.WOMAN)) .collect(Collectors.toList()); }