При глубине 0 вывод такой:
[]
[][0, 1, 3]
[][0, 1, 2, 3, 5, 7]
[2, 5, 7][0, 1, 2, 3, 5, 6, 7]
[2, 5, 6, 7]package com.javarush.task.task36.task3611;
import java.util.HashSet;
import java.util.Set;
/*
Сколько у человека потенциальных друзей?
*/
public class Solution {
private boolean[][] humanRelationships;
public static void main(String[] args) {
Solution solution = new Solution();
solution.humanRelationships = generateRelationships();
Set<Integer> allFriendsAndPotentialFriends = solution.getAllFriendsAndPotentialFriends(4, 2);
System.out.println(allFriendsAndPotentialFriends); // Expected: [0, 1, 2, 3, 5, 7]
Set<Integer> potentialFriends = solution.removeFriendsFromSet(allFriendsAndPotentialFriends, 4);
System.out.println(potentialFriends); // Expected: [2, 5, 7]
}
public Set<Integer> getAllFriendsAndPotentialFriends(int index, int deep) {
Set<Integer> setResult = null;
if (deep == 0) return new HashSet<>();
if (deep == 1) {
setResult = new HashSet<>();
for (int i = 0; i < humanRelationships.length; i++) {
if ((i < index) && (index < humanRelationships.length) && humanRelationships[index][i])
setResult.add(i);
else if ((i > index) && humanRelationships[i][index]) setResult.add(i);
}
}
if (deep > 1) {
setResult = new HashSet<>();
for (int i = 0; i < humanRelationships.length; i++) {
if ((i < index) && (index < humanRelationships.length) && humanRelationships[index][i])
setResult.add(i);
else if ((i > index) && humanRelationships[i][index]) setResult.add(i);
}
Set<Integer> setFriends = new HashSet<>();
for (int i = 0; i < deep--; i++) {
for (Integer in : setResult) {
for (int i1 = 0; i1 < humanRelationships.length; i1++) {
if ((i1 < in) && (in < humanRelationships.length) && humanRelationships[in][i1])
setFriends.add(i1);
else if ((i1 > in) && humanRelationships[i1][in]) setFriends.add(i1);
}
}
setResult.addAll(setFriends);
}
setResult.remove(index);
}
return setResult;
}
// Remove from the set the people with whom you already have a relationship
public Set<Integer> removeFriendsFromSet(Set<Integer> set, int index) {
for (int i = 0; i < humanRelationships.length; i++) {
if ((i < index) && (index < humanRelationships.length) && humanRelationships[index][i]) {
set.remove(i);
} else if ((i > index) && humanRelationships[i][index]) {
set.remove(i);
}
}
return set;
}
// Return test data
private static boolean[][] generateRelationships() {
return new boolean[][]{
{true}, //0
{true, true}, //1
{false, true, true}, //2
{false, false, false, true}, //3
{true, true, false, true, true}, //4
{true, false, true, false, false, true}, //5
{false, false, false, false, false, true, true}, //6
{false, false, false, true, false, false, false, true} //7
};
}
}