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1 | 1 | package aminetti.adventofcode2024.day05; |
2 | 2 |
|
3 | | -import aminetti.adventofcode2023.day05.SeedFertilizer; |
4 | | -import com.google.common.collect.Lists; |
5 | 3 | import org.slf4j.Logger; |
6 | 4 | import org.slf4j.LoggerFactory; |
7 | 5 |
|
@@ -124,7 +122,70 @@ private boolean isInOrder(List<String> pageList) { |
124 | 122 |
|
125 | 123 |
|
126 | 124 | public long solvePart2() { |
| 125 | + LOGGER.info("Rules: {}", rules); |
| 126 | + LOGGER.info("All pages: {}", allPages); |
| 127 | + |
| 128 | + |
| 129 | + List<List<String>> unOrderedLists = allPages.stream().filter(x -> !isInOrder(x)).collect(Collectors.toList()); |
| 130 | + |
| 131 | + long sum = 0; |
| 132 | + for (List<String> pageList : unOrderedLists) { |
| 133 | + LOGGER.info("Ordering {}", pageList); |
| 134 | + List<String> orderedList = orderList(pageList); |
| 135 | + String middlePage = orderedList.get(pageList.size() / 2); |
| 136 | + LOGGER.info("Ordered the list {} in this way {}; and the middle element is {}", pageList, orderedList, middlePage); |
| 137 | + sum += Long.parseLong(middlePage); |
| 138 | + |
| 139 | + } |
| 140 | + |
| 141 | + |
| 142 | + return sum; |
| 143 | + } |
| 144 | + |
| 145 | + private List<String> orderList(List<String> pageList) { |
| 146 | + Map<String, Integer> inEdgeCount = pageList.stream().collect(Collectors.toMap(Function.identity(), (x) -> 0)); |
| 147 | + for (String p : rules.keySet()) { |
| 148 | + for (String v : rules.get(p)) { |
| 149 | + if (pageList.contains(v) && pageList.contains(p)) { |
| 150 | + inEdgeCount.put(v, inEdgeCount.get(v) + 1); |
| 151 | + } |
| 152 | + } |
| 153 | + } |
| 154 | + LOGGER.info("The pages {} have this inEdgeCount: {}", pageList, inEdgeCount); |
| 155 | + List<String> firstElements = inEdgeCount.entrySet().stream() |
| 156 | + .filter(e -> e.getValue() == 0) |
| 157 | + .map(Map.Entry::getKey) |
| 158 | + .collect(Collectors.toList()); |
| 159 | + |
| 160 | + List<List<String>> partialOrder = new ArrayList<>(); |
| 161 | + partialOrder.add(firstElements); |
| 162 | + |
| 163 | + for (int i = 0; i < partialOrder.size(); i++) { |
| 164 | + List<String> level = partialOrder.get(i); |
| 165 | + if (level.isEmpty()) { |
| 166 | + break; |
| 167 | + } |
| 168 | + List<String> nextLevel = new ArrayList<>(); |
| 169 | + partialOrder.add(nextLevel); |
| 170 | + for (String e : level) { |
| 171 | + if (!rules.containsKey(e)) { |
| 172 | + continue; |
| 173 | + } |
| 174 | + for (String v : rules.get(e)) { |
| 175 | + if (!pageList.contains(v)) { |
| 176 | + continue; |
| 177 | + } |
| 178 | + Integer inEdgesForV = inEdgeCount.get(v); |
| 179 | + inEdgesForV--; |
| 180 | + inEdgeCount.put(v, inEdgesForV); |
| 181 | + if (inEdgesForV == 0) { |
| 182 | + nextLevel.add(v); |
| 183 | + } |
| 184 | + } |
| 185 | + } |
| 186 | + } |
| 187 | + ArrayList<String> unordered = new ArrayList<>(pageList); |
| 188 | + return partialOrder.stream().flatMap(x -> x.stream()).toList(); |
127 | 189 |
|
128 | | - return 0; |
129 | 190 | } |
130 | 191 | } |
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