-
Notifications
You must be signed in to change notification settings - Fork 0
/
Day20.java
369 lines (317 loc) · 9.53 KB
/
Day20.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Day20 {
public static void main(String[] args) throws IOException {
List<String> lines = Files.readAllLines(Paths.get("input20.txt"));
Map<Long, Tile> tilesMap = new HashMap<>();
List<Tile> tiles = new ArrayList<>();
Tile tile = new Tile();
for (String line : lines) {
if (line.isEmpty()) {
tiles.add(tile);
tilesMap.put(tile.id, tile);
tile = new Tile();
} else if (line.startsWith("Tile")) {
tile.id = Long.parseLong(line.substring(line.indexOf(" "), line.length() - 1).trim());
} else {
tile.cameras.add(line);
}
}
tiles.add(tile);
tilesMap.put(tile.id, tile);
long prod = 1L;
Map<Long, String> corners = new HashMap<>();
for (Tile t1 : tiles) {
boolean neighbour_up = false, neighbour_down = false, neighbour_left = false, neighbour_right = false;
int neighbours = 0;
for (Tile t2 : tiles) {
if (t1.id == t2.id)
continue;
if (isBorderWith(t1.getTop(), t2)) {
neighbour_up = true;
++neighbours;
}
if (isBorderWith(t1.getLeft(), t2)) {
neighbour_left = true;
++neighbours;
}
if (isBorderWith(t1.getRight(), t2)) {
neighbour_right = true;
++neighbours;
}
if (isBorderWith(t1.getBottom(), t2)) {
neighbour_down = true;
++neighbours;
}
}
if (neighbours == 2) {
prod *= t1.id;
if (neighbour_up == false && neighbour_left == false)
corners.put(t1.id, "nw");
if (neighbour_up == false && neighbour_right == false)
corners.put(t1.id, "ne");
if (neighbour_down == false && neighbour_left == false)
corners.put(t1.id, "sw");
if (neighbour_down == false && neighbour_right == false)
corners.put(t1.id, "se");
}
}
System.out.println(prod);
Tile upLeft = null;
Long corner = corners.entrySet().iterator().next().getKey();
if (corners.get(corner).equals("nw")) {
upLeft = tilesMap.get(corner);
} else if (corners.get(corner).equals("ne")) {
upLeft = rotate90(tilesMap.get(corner), 3);
} else if (corners.get(corner).equals("se")) {
upLeft = rotate90(tilesMap.get(corner), 2);
} else {
upLeft = rotate90(tilesMap.get(corner), 1);
}
List<String> image = createImage(upLeft, tiles);
int monsters = findMonsters(image);
long water = image.stream().flatMap(e -> e.chars().boxed()).filter(e -> e == '#').count();
long onlyWater = water - monsters * 15;
System.out.println(onlyWater);
}
public static int findMonsters(List<String> imageOriginal) {
String[] monster = {
" #",
"# ## ## ###",
" # # # # # # "};
List<Pair<Integer, Integer>> monsterCoordinates = new ArrayList<>();
for(int i = 0; i < monster.length; i++) {
for(int j = 0; j < monster[i].length(); j++) {
if(monster[i].charAt(j) == '#') monsterCoordinates.add(new Pair<>(i, j));
}
}
int monsters = 0;
int imageSize = imageOriginal.size();
int monsterH = monster.length;
int monsterW = monster[0].length();
List<List<String>> images = getAllImages(imageOriginal);
for(List<String> image : images) {
for(int i = 0; i < imageSize - monsterH; i++) {
for(int j = 0; j < imageSize - monsterW; j++) {
boolean isMonster = true;
for(Pair<Integer, Integer> p : monsterCoordinates) {
if(image.get(i + p.getFirst()).charAt(j + p.getSecond()) == '#') continue;
else isMonster = false;
}
if(isMonster) ++monsters;
}
}
}
return monsters;
}
private static List<List<String>> getAllImages(List<String> imageOriginal) {
List<List<String>> images = new ArrayList<>();
Tile t = new Tile();
t.cameras = imageOriginal;
for(int i = 0; i < 4; i++) {
Tile newTile = rotate90(t, i);
images.add(newTile.cameras);
t = newTile;
}
t = flip(t);
for(int i = 0; i < 4; i++) {
Tile newTile = rotate90(t, i);
images.add(newTile.cameras);
t = newTile;
}
return images;
}
private static List<String> createImage(Tile upLeft, List<Tile> tiles) {
int size = (int) Math.sqrt(tiles.size());
int rowSize = upLeft.getSize();
List<List<Tile>> tileImage = new ArrayList<>();
Set<Long> usedTiles = new HashSet<>();
for (int i = 0; i < size; i++) {
List<Tile> row = matchRow(upLeft, size, tiles, usedTiles);
tileImage.add(row);
upLeft = findMatchingTile(row.get(0), row.get(0).cameras.get(rowSize - 1), 'n' ,tiles, usedTiles);
for(Tile t : row) usedTiles.add(t.id);
}
List<String> image = removeBorders(tileImage);
return image;
}
private static List<Tile> matchRow(Tile left, int size, List<Tile> tiles, Set<Long> usedTiles) {
List<Tile> row = new ArrayList<>();
row.add(left);
for(int i = 1; i < size; i++) {
left = findMatchingTile(left, left.getRight(), 'w', tiles, usedTiles);
row.add(left);
}
return row;
}
private static Tile findMatchingTile(Tile neighbour, String border, char borderLooking, List<Tile> tiles, Set<Long> usedTiles) {
for(Tile t : tiles) {
if(usedTiles.contains(t.id) || t.id == neighbour.id) continue;
if(isBorderWith(border, t)) {
fixOrientation(t, border, borderLooking);
return t;
}
}
return null;
}
private static List<String> removeBorders(List<List<Tile>> tileImage) {
List<String> image = new ArrayList<>();
for (List<Tile> row : tileImage) {
for (int i = 1; i <= 8; i++) {
StringBuilder sb = new StringBuilder();
for (Tile t : row) {
sb.append(t.cameras.get(i).substring(1, 9));
}
String line = sb.toString();
image.add(line);
}
}
return image;
}
private static void fixOrientation(Tile t, String border, char borderLooking) {
StringBuilder sb = new StringBuilder();
String reversed = sb.append(border).reverse().toString();
if(borderLooking == 'n') {
if(border.equals(t.getTop())) {
return;
} else if(reversed.equals(t.getTop())) {
flip(t);
} else if(border.equals(t.getBottom())) {
flip(rotate90(t, 2));
} else if(reversed.equals(t.getBottom())) {
rotate90(t, 2);
} else if(border.equals(t.getRight())) {
rotate90(t, 3);
} else if(reversed.equals(t.getRight())) {
flip(rotate90(t, 3));
} else if(border.equals(t.getLeft())) {
flip(rotate90(t, 1));
} else if(reversed.equals(t.getLeft())) {
rotate90(t, 1);
}
} else if(borderLooking == 'w') {
if(border.equals(t.getLeft())) {
return;
} else if(reversed.equals(t.getLeft())) {
rotate90(flip(t), 2);
} else if(border.equals(t.getRight())) {
flip(t);
} else if(reversed.equals(t.getRight())) {
rotate90(t, 2);
} else if(border.equals(t.getTop())) {
rotate90(flip(t), 3);
} else if(reversed.equals(t.getTop())) {
rotate90(t, 3);
} else if(border.equals(t.getBottom())) {
rotate90(t, 1);
} else if(reversed.equals(t.getBottom())) {
rotate90(flip(t), 1);
}
}
}
private static Tile rotate90(Tile tile, int times) {
times = times % 4;
int rowSize = tile.cameras.get(0).length();
while (times != 0) {
List<String> cameras = new ArrayList<>();
for (int i = 0; i < rowSize; i++) {
StringBuilder sb = new StringBuilder();
for (int j = tile.cameras.size() - 1; j >= 0; j--) {
sb.append(tile.cameras.get(j).charAt(i));
}
cameras.add(sb.toString());
}
--times;
tile.cameras = cameras;
}
return tile;
}
private static Tile flip(Tile t) {
List<String> cameras = new ArrayList<>();
for(String s : t.cameras) {
StringBuilder sb = new StringBuilder();
cameras.add(sb.append(s).reverse().toString());
}
t.cameras = cameras;
return t;
}
private static boolean isBorderWith(String border, Tile t2) {
StringBuilder sb = new StringBuilder();
String reversed = sb.append(border).reverse().toString();
if (border.equals(t2.getTop()) || border.equals(t2.getBottom())
|| border.equals(t2.getRight()) || border.equals(t2.getLeft()))
return true;
if (reversed.equals(t2.getTop()) || reversed.equals(t2.getBottom()) || reversed.equals(t2.getRight())
|| reversed.equals(t2.getLeft()))
return true;
return false;
}
}
class Tile {
long id;
List<String> cameras = new ArrayList<>();
public int getSize() {
return cameras.size();
}
public String getLeft() {
StringBuilder sb = new StringBuilder();
for(int i = 0; i < getSize(); i++) {
sb.append(cameras.get(i).charAt(0));
}
return sb.toString();
}
public String getRight() {
int size = getSize();
StringBuilder sb = new StringBuilder();
for(int i = 0; i < size; i++) {
sb.append(cameras.get(i).charAt(size-1));
}
return sb.toString();
}
public String getTop() {
return cameras.get(0);
}
public String getBottom() {
return cameras.get(getSize()-1);
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (String s : cameras)
sb.append(s).append("\n");
return sb.toString();
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((cameras == null) ? 0 : cameras.hashCode());
result = prime * result + (int) (id ^ (id >>> 32));
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Tile other = (Tile) obj;
if (cameras == null) {
if (other.cameras != null)
return false;
} else if (!cameras.equals(other.cameras))
return false;
if (id != other.id)
return false;
return true;
}
}