From daf2cd0dbffe69fef0cf103c479ad7e42f587820 Mon Sep 17 00:00:00 2001 From: Con Date: Tue, 9 Jun 2026 14:17:06 +0200 Subject: [PATCH 1/3] Solved stream practice --- .../java/practice/CandidateValidator.java | 28 ++++++++++- src/main/java/practice/StreamPractice.java | 47 ++++++++++++++++--- 2 files changed, 66 insertions(+), 9 deletions(-) diff --git a/src/main/java/practice/CandidateValidator.java b/src/main/java/practice/CandidateValidator.java index 8d2e56c0e..5120c3e65 100644 --- a/src/main/java/practice/CandidateValidator.java +++ b/src/main/java/practice/CandidateValidator.java @@ -1,5 +1,29 @@ package practice; -public class CandidateValidator { - //write your code here +import java.util.function.Predicate; +import model.Candidate; + +public class CandidateValidator implements Predicate { + private static final int MIN_CANDIDATE_AGE = 35; + private static final String CANDIDATE_NATIONALITY = "Ukrainian"; + private static final int LIVING_TIME_IN_COUNTRY = 10; + + // string has following view: "2002-2015" + private static Integer timeLivingInCountry(String fromTo) { + String[] parts = fromTo.split("-"); + if (parts.length == 2) { + return Integer.parseInt(parts[1]) - Integer.parseInt(parts[0]); + } + + throw new IllegalArgumentException("Invalid from-to: " + fromTo); + } + + @Override + public boolean test(Candidate candidate) { + return candidate.getAge() >= MIN_CANDIDATE_AGE + && candidate.getNationality().equals(CANDIDATE_NATIONALITY) + && candidate.isAllowedToVote() + && timeLivingInCountry(candidate.getPeriodsInUkr()) + >= LIVING_TIME_IN_COUNTRY; + } } diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 57b1ca2e2..6b1dbc758 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -1,8 +1,12 @@ package practice; -import java.util.Collections; +import java.util.Arrays; import java.util.List; +import java.util.NoSuchElementException; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.stream.Collectors; import model.Candidate; +import model.Cat; import model.Person; public class StreamPractice { @@ -14,7 +18,12 @@ 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(str -> Arrays.stream(str.split(","))) + .mapToInt(Integer::parseInt) + .filter(i -> i % 2 == 0) + .min() + .orElseThrow(() -> new RuntimeException("Can't get min value from list: " + numbers)); } /** @@ -23,7 +32,15 @@ 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; + AtomicInteger index = new AtomicInteger(0); + + return numbers.stream() + .mapToDouble(elem -> index.getAndIncrement() + % 2 == 0 ? elem.doubleValue() + : elem.doubleValue() - 1) + .filter(i -> i % 2 == 1) + .average() + .orElseThrow(NoSuchElementException::new); } /** @@ -35,7 +52,10 @@ 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(); + return peopleList.stream() + .filter(person -> Person.Sex.MAN.equals(person.getSex()) + && person.getAge() >= fromAge && person.getAge() <= toAge) + .collect(Collectors.toList()); } /** @@ -50,7 +70,11 @@ public List selectMenByAge(List peopleList, int fromAge, int toA */ public List getWorkablePeople(int fromAge, int femaleToAge, int maleToAge, List peopleList) { - return Collections.emptyList(); + return peopleList.stream() + .filter(person -> Person.Sex.MAN.equals(person.getSex()) + ? person.getAge() >= fromAge && person.getAge() <= maleToAge + : person.getAge() >= fromAge && person.getAge() <= femaleToAge) + .collect(Collectors.toList()); } /** @@ -59,7 +83,12 @@ 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(person -> Person.Sex.WOMAN.equals(person.getSex()) + && person.getAge() >= femaleAge) + .flatMap(woman -> woman.getCats().stream()) + .map(Cat::getName) + .collect(Collectors.toList()); } /** @@ -75,6 +104,10 @@ public List getCatsNames(List peopleList, int femaleAge) { * parametrized with Candidate in CandidateValidator. */ public List validateCandidates(List candidates) { - return Collections.emptyList(); + return candidates.stream() + .filter(new CandidateValidator()) + .map(Candidate::getName) + .sorted() + .collect(Collectors.toList()); } } From 56ad489a40978a9afe31fd34d6c00659b3c24909 Mon Sep 17 00:00:00 2001 From: Con Date: Tue, 9 Jun 2026 14:35:59 +0200 Subject: [PATCH 2/3] Changed getOddNumsAverage solution --- src/main/java/practice/StreamPractice.java | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index 6b1dbc758..a5b657d55 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -5,6 +5,8 @@ import java.util.NoSuchElementException; import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; +import java.util.stream.IntStream; + import model.Candidate; import model.Cat; import model.Person; @@ -32,13 +34,12 @@ 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) { - AtomicInteger index = new AtomicInteger(0); - return numbers.stream() - .mapToDouble(elem -> index.getAndIncrement() - % 2 == 0 ? elem.doubleValue() - : elem.doubleValue() - 1) - .filter(i -> i % 2 == 1) + return IntStream.range(0, numbers.size()) + .mapToDouble(index -> index % 2 == 0 + ? numbers.get(index).doubleValue() + : numbers.get(index).doubleValue() - 1) + .filter(i -> (int)i % 2 == 1 || (int)i % 2 == -1) .average() .orElseThrow(NoSuchElementException::new); } From 7139189668e9c586374e30633e5651cc53405860 Mon Sep 17 00:00:00 2001 From: Con Date: Tue, 9 Jun 2026 14:37:34 +0200 Subject: [PATCH 3/3] Fixed styles --- src/main/java/practice/StreamPractice.java | 2 -- 1 file changed, 2 deletions(-) diff --git a/src/main/java/practice/StreamPractice.java b/src/main/java/practice/StreamPractice.java index a5b657d55..77bc33eaa 100644 --- a/src/main/java/practice/StreamPractice.java +++ b/src/main/java/practice/StreamPractice.java @@ -3,10 +3,8 @@ import java.util.Arrays; import java.util.List; import java.util.NoSuchElementException; -import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; import java.util.stream.IntStream; - import model.Candidate; import model.Cat; import model.Person;