Created
December 10, 2020 09:43
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package aoc; | |
import java.io.IOException; | |
import java.nio.file.Files; | |
import java.nio.file.Paths; | |
import java.util.HashMap; | |
import java.util.Map; | |
public class Day10 { | |
public static void main(String[] args) throws IOException { | |
int[] vals = Files.readAllLines(Paths.get("input10.txt")).stream().mapToInt(n -> Integer.parseInt(n)).sorted().toArray(); | |
int n1 = 0; | |
int n3 = 1; // counting the device too, it's a 3 difference | |
int prev = 0; | |
for (int i = 0; i < vals.length; i++) { | |
int diff = vals[i]-prev; | |
if(diff==1) n1++; | |
if(diff==3) n3++; | |
if(diff>3) throw new RuntimeException("hole!"); | |
prev = vals[i]; | |
} | |
System.out.println(n1*n3); | |
long n = countFrom(vals, -1, new HashMap<>()); // -1 since we start from the plug | |
System.out.println(n); | |
} | |
private static long countFrom(int[] vals, int pos, Map<Integer, Long> calculated) { | |
long res = 0; | |
if(calculated.containsKey(pos)) | |
{ | |
res = calculated.get(pos); | |
} | |
else | |
{ | |
int val = pos <0 ? 0 : vals[pos]; | |
for (int i = pos+1; i < vals.length; i++) { | |
int v2 = vals[i]; | |
if(v2-val <= 3) | |
{ | |
res += countFrom(vals, i, calculated); | |
} | |
else | |
{ | |
break; | |
} | |
} | |
if(pos==(vals.length-1)) | |
{ | |
res++; | |
} | |
System.out.println("putting "+pos+" "+res); | |
calculated.put(pos, res); | |
} | |
return res; | |
} | |
} |
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