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Day10.java
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Day10.java
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package io.github.sirnikolai.days;
import io.github.sirnikolai.AbstractSolution;
import java.util.Arrays;
public class Day10 extends AbstractSolution {
@Override
public void Part1(String input) {
int[] in = toInteger(input.split("\n"));
Arrays.sort(in);
int oneJumps = 1;
int threeJumps = 1;
for(int i = 1; i < in.length; i++) {
int diff = in[i] - in[i-1];
if(diff == 1) {
oneJumps++;
} else if(diff == 3) {
threeJumps++;
}
}
System.out.println(oneJumps * threeJumps);
}
@Override
public void Part2(String input) {
int[] in = toInteger(input.split("\n"));
Arrays.sort(in);
System.out.println(backtrack(in, -1, 0, in[in.length - 1]));
}
private long backtrack(int[] arr, int cur, int tally, int target) {
long[] arr2 = new long[arr.length+1];
arr2[0] = 1;
for(int i = 1; i < arr2.length; i++) {
if(arr[i-1] <= 3) {
arr2[i] = 1;
}
for(int j = Math.max(i-3, 1); j < i; j++) {
if(arr[i-1] - arr[j-1] <= 3) {
arr2[i] += arr2[j];
}
}
}
return arr2[arr2.length-1];
// if(target == tally) {
// return 1l;
// } else if(target < tally) {
// return 0l;
// }
//
// long sum = 0l;
//
// for(int i = cur + 1; i < arr.length; i++) {
// if(arr[i] - tally > 3) {
// break;
// }
//
// sum += backtrack(arr, i, arr[i], target);
// }
//
// return sum;
}
private int[] toInteger(String[] in) {
int[] out = new int[in.length];
for(int i = 0; i < in.length; i++) {
out[i] = Integer.parseInt(in[i]);
}
return out;
}
}