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import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.ArrayList;
public class day13 {
public static void main(String args[]) throws IOException {
RandomAccessFile input = new RandomAccessFile("input", "r");
System.out.println("Day 13 Part 1: " + part1(input));
input.seek(0);
System.out.println("Day 13 Part 2: " + part2(input));
input.close();
}
public static String part1(RandomAccessFile input) throws IOException {
ArrayList<Pattern> patterns = new ArrayList<>();
Pattern pattern;
while ((pattern = getPattern(input)) != null) {
patterns.add(pattern);
}
int sum = 0;
for (Pattern p: patterns) {
sum += p.mirrorLine();
}
return Integer.toString(sum);
}
public static String part2(RandomAccessFile input) throws IOException {
ArrayList<Pattern> patterns = new ArrayList<>();
Pattern pattern;
while ((pattern = getPattern(input)) != null) {
patterns.add(pattern);
}
int sum = 0;
for (Pattern p: patterns) {
int line = p.mirrorLine();
findSmudge:
for (int r = 0; r < p.rows(); r++) {
for (int c = 0; c < p.cols(); c++) {
p.repair(r, c);
int newline = p.differentMirrorLine(line);
p.repair(r, c);
if (newline > 0) {
sum += newline;
break findSmudge;
}
}
}
}
return Integer.toString(sum);
}
private static Pattern getPattern(RandomAccessFile input) throws IOException {
Pattern pattern = new Pattern();
String line = input.readLine();
while (line != null && line.length() != 0) {
pattern.add(line);
line = input.readLine();
}
if (pattern.rows() > 0) {
return pattern;
} else {
return null;
}
}
private static enum Terrain {
Ash,
Rock
}
private static class Pattern {
ArrayList<ArrayList<Terrain>> pattern;
public Pattern() {
this.pattern = new ArrayList<>();
}
public void add(String line) {
ArrayList<Terrain> row = new ArrayList<>();
for (char ch: line.toCharArray()) {
if (ch == '#') {
row.add(Terrain.Rock);
} else if (ch == '.') {
row.add(Terrain.Ash);
}
}
this.pattern.add(row);
}
public int rows() {
return this.pattern.size();
}
public int cols() {
return this.pattern.get(0).size();
}
public int mirrorLine() {
for (int i = 1; i < this.cols(); i++) {
boolean isMirrorLine = true;
for (ArrayList<Terrain> row: this.pattern) {
int l = i - 1, r = i;
while (isMirrorLine && l >= 0 && r < this.cols()) {
if (row.get(l) != row.get(r)) {
isMirrorLine = false;
}
l -= 1;
r += 1;
}
}
if (isMirrorLine) {
return i;
}
}
for (int i = 1; i < this.rows(); i++) {
boolean isMirrorLine = true;
int a = i - 1, b = i;
while (isMirrorLine && a >= 0 && b < this.rows()) {
ArrayList<Terrain> ra = this.pattern.get(a);
ArrayList<Terrain> rb = this.pattern.get(b);
for (int j = 0; j < this.cols(); j++) {
if (ra.get(j) != rb.get(j)) {
isMirrorLine = false;
break;
}
}
a -= 1;
b += 1;
}
if (isMirrorLine) {
return 100 * i;
}
}
return 0;
}
public int differentMirrorLine(int oldLine) {
for (int i = 1; i < this.cols(); i++) {
boolean isMirrorLine = true;
for (ArrayList<Terrain> row: this.pattern) {
int l = i - 1, r = i;
while (isMirrorLine && l >= 0 && r < this.cols()) {
if (row.get(l) != row.get(r)) {
isMirrorLine = false;
}
l -= 1;
r += 1;
}
}
if (isMirrorLine && i != oldLine) {
return i;
}
}
for (int i = 1; i < this.rows(); i++) {
boolean isMirrorLine = true;
int a = i - 1, b = i;
while (isMirrorLine && a >= 0 && b < this.rows()) {
ArrayList<Terrain> ra = this.pattern.get(a);
ArrayList<Terrain> rb = this.pattern.get(b);
for (int j = 0; j < this.cols(); j++) {
if (ra.get(j) != rb.get(j)) {
isMirrorLine = false;
break;
}
}
a -= 1;
b += 1;
}
if (isMirrorLine && (100 * i) != oldLine) {
return 100 * i;
}
}
return 0;
}
public void repair(int row, int col) {
Terrain smudge = this.pattern.get(row).get(col);
if (smudge == Terrain.Rock) {
this.pattern.get(row).set(col, Terrain.Ash);
} else {
this.pattern.get(row).set(col, Terrain.Rock);
}
}
}
}
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