commit 2f5c51b28c1b0bc2f932aeeb6c068799494b0195
parent 7d77e0cc6ded255d08f27d9148bdc1efe0d602e1
Author: Louis Burda <quent.burda@gmail.com>
Date: Wed, 17 Nov 2021 17:55:20 +0100
Add day 12
Diffstat:
9 files changed, 511 insertions(+), 0 deletions(-)
diff --git a/libs/include/maxint.h b/libs/include/maxint.h
@@ -58,6 +58,8 @@ void mi_mul(struct maxint *m1, const struct maxint *m2); // m1 *= m2
void mi_div(struct maxint *m1, struct maxint *m2, const struct maxint *m3); // m1 /= m3, m2 = m1 % m3
void mi_swap(struct maxint *m1, struct maxint *m2); // m1 <=> m2
int mi_cmp(const struct maxint *m1, const struct maxint *m2); // m1 < m2 ? m2 > m1 ? 1 : 0 : -1
+void mi_gcm(struct maxint *m1, const struct maxint *m2); // m1 = gcm(m1, m2)
+void mi_lcm(struct maxint *m1, const struct maxint *m2); // m1 = lcm(m1, m2)
char * mi_convstr(char *alloc, const struct maxint *m, int base, const char *alph);
char * mi_hexstr(char *alloc, const struct maxint *m, int cap);
diff --git a/libs/src/maxint.c b/libs/src/maxint.c
@@ -244,6 +244,42 @@ mi_cmp(const struct maxint *m1, const struct maxint *m2)
return 0;
}
+void
+mi_gcd(struct maxint *m1, const struct maxint *m2)
+{
+ struct maxint rem, b;
+
+ rem = b = MI_INIT;
+ mi_setv(&rem, 0, MI_POS);
+ mi_set(&b, m2);
+
+ do {
+ mi_div(m1, &rem, &b);
+ mi_swap(m1, &b);
+ mi_swap(&b, &rem);
+ } while (!mi_zero(&b));
+
+ mi_free(&rem);
+ mi_free(&b);
+}
+
+void
+mi_lcm(struct maxint *m1, const struct maxint *m2)
+{
+ struct maxint lcm;
+
+ lcm = MI_INIT;
+ mi_set(&lcm, m1);
+
+ mi_gcd(m1, m2);
+ mi_swap(m1, &lcm);
+
+ mi_mul(m1, m2);
+ mi_div(m1, NULL, &lcm);
+
+ mi_free(&lcm);
+}
+
int
mi_lastset(const struct maxint *m1)
{
diff --git a/src/12/Makefile b/src/12/Makefile
@@ -0,0 +1,13 @@
+CFLAGS = -g -I ../../libs/include -L ../../libs/build
+LDLIBS = -laoc
+
+all: lib main
+
+clean:
+ rm main
+
+lib:
+ make -C ../../libs
+
+main: main.c ../../libs/build/*
+ $(CC) -o $@ $< $(CFLAGS) $(LDLIBS)
diff --git a/src/12/input b/src/12/input
@@ -0,0 +1,4 @@
+<x=-2, y=9, z=-5>
+<x=16, y=19, z=9>
+<x=0, y=3, z=6>
+<x=11, y=0, z=11>
diff --git a/src/12/main.c b/src/12/main.c
@@ -0,0 +1,190 @@
+#include "aoc.h"
+#include "memvec.h"
+#include "maxint.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+
+struct vec3 {
+ union {
+ struct {
+ int x, y, z;
+ };
+ int axis[3];
+ };
+};
+
+struct moon {
+ struct vec3 pos, vel;
+};
+
+void
+moons_init(struct memvec *vec)
+{
+ char *p, *p2, *tok, *val;
+ struct moon m;
+ int i;
+
+ m.vel = (struct vec3) { 0, 0, 0 };
+ memvec_init(vec, 100, sizeof(struct moon));
+
+ tok = aoc.input;
+ while ((p = strchr(tok, '\n'))) {
+ val = tok;
+ for (i = 0; i < 3 && (val = strchr(val + 1, '=')); i++)
+ m.pos.axis[i] = strtol(val + 1, NULL, 10);
+ memvec_add(vec, &m);
+ tok = p + 1;
+ }
+}
+
+void
+moons_free(struct memvec *vec)
+{
+ memvec_free(vec);
+}
+
+int
+get_energy(struct moon *m)
+{
+ int pot, kin;
+
+ pot = ABS(m->pos.x);
+ pot += ABS(m->pos.y);
+ pot += ABS(m->pos.z);
+
+ kin = ABS(m->vel.x);
+ kin += ABS(m->vel.y);
+ kin += ABS(m->vel.z);
+
+ return pot * kin;
+}
+
+int
+rel(int a, int b)
+{
+ if (a == b) return 0;
+ return (a < b) ? +1 : -1;
+}
+
+void
+sim_step(struct memvec *moons, int show)
+{
+ struct moon *m1, *m2;
+ static int step = 0;
+ int i, k, l, relv;
+
+ /* initial state */
+ for (i = 0; !step && show && i < memvec_len(moons); i++) {
+ m1 = memvec_get(moons, i);
+ debug("%i: %i %i %i , %i %i %i = %i\n", step, m1->pos.x, m1->pos.y, m1->pos.z,
+ m1->vel.x, m1->vel.y, m1->vel.z, get_energy(m1));
+ }
+
+ /* update velocity */
+ for (i = 0; i < memvec_len(moons); i++) {
+ for (k = i + 1; k < memvec_len(moons); k++) {
+ m1 = memvec_get(moons, i);
+ m2 = memvec_get(moons, k);
+
+ for (l = 0; l < 3; l++) {
+ relv = rel(m1->pos.axis[l], m2->pos.axis[l]);
+ m1->vel.axis[l] += relv;
+ m2->vel.axis[l] -= relv;
+ }
+ }
+ }
+
+ /* update position */
+ for (i = 0; i < memvec_len(moons); i++) {
+ m1 = memvec_get(moons, i);
+ for (k = 0; k < 3; k++)
+ m1->pos.axis[k] += m1->vel.axis[k];
+
+ if (show) debug("%i: %i %i %i , %i %i %i = %i\n", step+1,
+ m1->pos.x, m1->pos.y, m1->pos.z, m1->vel.x,
+ m1->vel.y, m1->vel.z, get_energy(m1));
+ }
+
+ step++;
+}
+
+void
+part1(void)
+{
+ struct memvec moons;
+ struct moon *m;
+ int i, energy;
+
+ moons_init(&moons);
+
+ for (i = 0; i < 1000; i++)
+ sim_step(&moons, aoc.debug);
+
+ energy = 0;
+ for (i = 0; i < memvec_len(&moons); i++)
+ energy += get_energy(memvec_get(&moons, i));
+
+ aoc.answer = CHKP(aprintf("%i", energy));
+ aoc.solution = "12053";
+
+ moons_free(&moons);
+}
+
+void
+part2(void)
+{
+ struct memvec init, moons;
+ struct maxint cycles[3];
+ struct maxint *steps;
+ struct moon *m1, *m2;
+ int same, poseq, veleq;
+ int i, k;
+ char *s;
+
+ moons_init(&init);
+
+ s = NULL;
+ for (i = 0; i < 3; i++) {
+ moons_init(&moons);
+
+ same = 0;
+ cycles[i] = MI_INIT;
+ mi_setv(&cycles[i], 0, MI_POS);
+
+ while (!same) {
+ sim_step(&moons, aoc.debug == 2);
+
+ same = 1;
+ for (k = 0; k < memvec_len(&moons); k++) {
+ m1 = memvec_get(&moons, k);
+ m2 = memvec_get(&init, k);
+ veleq = m1->pos.axis[i] == m2->pos.axis[i];
+ poseq = m1->vel.axis[i] == m2->vel.axis[i];
+ if (!veleq || !poseq) {
+ same = 0;
+ break;
+ }
+ }
+
+ mi_add(&cycles[i], &mi_one);
+ }
+
+ debug("Cycles Axis %i: %s\n", i+1, (s = mi_decstr(s, &cycles[i])));
+
+ moons_free(&moons);
+ }
+ free(s);
+
+ steps = &cycles[0];
+ for (i = 1; i < 3; i++)
+ mi_lcm(steps, &cycles[i]);
+
+ aoc.answer = mi_decstr(NULL, steps);
+ aoc.solution = "320380285873116";
+
+ for (i = 0; i < 3; i++)
+ mi_free(&cycles[i]);
+
+ moons_free(&init);
+}
diff --git a/src/12/part1 b/src/12/part1
@@ -0,0 +1,208 @@
+--- Day 12: The N-Body Problem ---
+
+The space near Jupiter is not a very safe place; you need to be careful of a big distracting red
+spot, extreme radiation, and a whole lot of moons swirling around. You decide to start by tracking
+the four largest moons: [1m[37mIo[0m, [1m[37mEuropa[0m, [1m[37mGanymede[0m, and
+[1m[37mCallisto[0m.
+
+After a brief scan, you calculate the [1m[37mposition of each moon[0m (your puzzle input). You
+just need to [1m[37msimulate their motion[0m so you can avoid them.
+
+Each moon has a 3-dimensional position (x, y, and z) and a 3-dimensional velocity. The position of
+each moon is given in your scan; the x, y, and z velocity of each moon starts at 0.
+
+Simulate the motion of the moons in [1m[37mtime steps[0m. Within each time step, first update the
+velocity of every moon by applying [1m[37mgravity[0m. Then, once all moons' velocities have been
+updated, update the position of every moon by applying [1m[37mvelocity[0m. Time progresses by one
+step once all of the positions are updated.
+
+To apply [1m[37mgravity[0m, consider every [1m[37mpair[0m of moons. On each axis (x, y, and
+z), the velocity of each moon changes by [1m[37mexactly +1 or -1[0m to pull the moons together.
+For example, if Ganymede has an x position of 3, and Callisto has a x position of 5, then Ganymede's
+x velocity [1m[37mchanges by +1[0m (because 5 > 3) and Callisto's x velocity [1m[37mchanges by
+-1[0m (because 3 < 5). However, if the positions on a given axis are the same, the velocity on that
+axis [1m[37mdoes not change[0m for that pair of moons.
+
+Once all gravity has been applied, apply [1m[37mvelocity[0m: simply add the velocity of each moon
+to its own position. For example, if Europa has a position of x=1, y=2, z=3 and a velocity of x=-2,
+y=0,z=3, then its new position would be x=-1, y=2, z=6. This process does not modify the velocity of
+any moon.
+
+For example, suppose your scan reveals the following positions:
+
+<x=-1, y=0, z=2>
+<x=2, y=-10, z=-7>
+<x=4, y=-8, z=8>
+<x=3, y=5, z=-1>
+
+Simulating the motion of these moons would produce the following:
+
+After 0 steps:
+pos=<x=-1, y= 0, z= 2>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 2, y=-10, z=-7>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 4, y= -8, z= 8>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 3, y= 5, z=-1>, vel=<x= 0, y= 0, z= 0>
+
+After 1 step:
+pos=<x= 2, y=-1, z= 1>, vel=<x= 3, y=-1, z=-1>
+pos=<x= 3, y=-7, z=-4>, vel=<x= 1, y= 3, z= 3>
+pos=<x= 1, y=-7, z= 5>, vel=<x=-3, y= 1, z=-3>
+pos=<x= 2, y= 2, z= 0>, vel=<x=-1, y=-3, z= 1>
+
+After 2 steps:
+pos=<x= 5, y=-3, z=-1>, vel=<x= 3, y=-2, z=-2>
+pos=<x= 1, y=-2, z= 2>, vel=<x=-2, y= 5, z= 6>
+pos=<x= 1, y=-4, z=-1>, vel=<x= 0, y= 3, z=-6>
+pos=<x= 1, y=-4, z= 2>, vel=<x=-1, y=-6, z= 2>
+
+After 3 steps:
+pos=<x= 5, y=-6, z=-1>, vel=<x= 0, y=-3, z= 0>
+pos=<x= 0, y= 0, z= 6>, vel=<x=-1, y= 2, z= 4>
+pos=<x= 2, y= 1, z=-5>, vel=<x= 1, y= 5, z=-4>
+pos=<x= 1, y=-8, z= 2>, vel=<x= 0, y=-4, z= 0>
+
+After 4 steps:
+pos=<x= 2, y=-8, z= 0>, vel=<x=-3, y=-2, z= 1>
+pos=<x= 2, y= 1, z= 7>, vel=<x= 2, y= 1, z= 1>
+pos=<x= 2, y= 3, z=-6>, vel=<x= 0, y= 2, z=-1>
+pos=<x= 2, y=-9, z= 1>, vel=<x= 1, y=-1, z=-1>
+
+After 5 steps:
+pos=<x=-1, y=-9, z= 2>, vel=<x=-3, y=-1, z= 2>
+pos=<x= 4, y= 1, z= 5>, vel=<x= 2, y= 0, z=-2>
+pos=<x= 2, y= 2, z=-4>, vel=<x= 0, y=-1, z= 2>
+pos=<x= 3, y=-7, z=-1>, vel=<x= 1, y= 2, z=-2>
+
+After 6 steps:
+pos=<x=-1, y=-7, z= 3>, vel=<x= 0, y= 2, z= 1>
+pos=<x= 3, y= 0, z= 0>, vel=<x=-1, y=-1, z=-5>
+pos=<x= 3, y=-2, z= 1>, vel=<x= 1, y=-4, z= 5>
+pos=<x= 3, y=-4, z=-2>, vel=<x= 0, y= 3, z=-1>
+
+After 7 steps:
+pos=<x= 2, y=-2, z= 1>, vel=<x= 3, y= 5, z=-2>
+pos=<x= 1, y=-4, z=-4>, vel=<x=-2, y=-4, z=-4>
+pos=<x= 3, y=-7, z= 5>, vel=<x= 0, y=-5, z= 4>
+pos=<x= 2, y= 0, z= 0>, vel=<x=-1, y= 4, z= 2>
+
+After 8 steps:
+pos=<x= 5, y= 2, z=-2>, vel=<x= 3, y= 4, z=-3>
+pos=<x= 2, y=-7, z=-5>, vel=<x= 1, y=-3, z=-1>
+pos=<x= 0, y=-9, z= 6>, vel=<x=-3, y=-2, z= 1>
+pos=<x= 1, y= 1, z= 3>, vel=<x=-1, y= 1, z= 3>
+
+After 9 steps:
+pos=<x= 5, y= 3, z=-4>, vel=<x= 0, y= 1, z=-2>
+pos=<x= 2, y=-9, z=-3>, vel=<x= 0, y=-2, z= 2>
+pos=<x= 0, y=-8, z= 4>, vel=<x= 0, y= 1, z=-2>
+pos=<x= 1, y= 1, z= 5>, vel=<x= 0, y= 0, z= 2>
+
+After 10 steps:
+pos=<x= 2, y= 1, z=-3>, vel=<x=-3, y=-2, z= 1>
+pos=<x= 1, y=-8, z= 0>, vel=<x=-1, y= 1, z= 3>
+pos=<x= 3, y=-6, z= 1>, vel=<x= 3, y= 2, z=-3>
+pos=<x= 2, y= 0, z= 4>, vel=<x= 1, y=-1, z=-1>
+
+Then, it might help to calculate the [1m[37mtotal energy in the system[0m. The total energy for a
+single moon is its [1m[37mpotential energy[0m multiplied by its [1m[37mkinetic energy[0m. A
+moon's [1m[37mpotential energy[0m is the sum of the absolute values of its x, y, and z position
+coordinates. A moon's [1m[37mkinetic energy[0m is the sum of the absolute values of its velocity
+coordinates. Below, each line shows the calculations for a moon's potential energy (pot), kinetic
+energy (kin), and total energy:
+
+Energy after 10 steps:
+pot: 2 + 1 + 3 = 6; kin: 3 + 2 + 1 = 6; total: 6 * 6 = 36
+pot: 1 + 8 + 0 = 9; kin: 1 + 1 + 3 = 5; total: 9 * 5 = 45
+pot: 3 + 6 + 1 = 10; kin: 3 + 2 + 3 = 8; total: 10 * 8 = 80
+pot: 2 + 0 + 4 = 6; kin: 1 + 1 + 1 = 3; total: 6 * 3 = 18
+Sum of total energy: 36 + 45 + 80 + 18 = [1m[37m179[0m
+
+In the above example, adding together the total energy for all moons after 10 steps produces the
+total energy in the system, [1m[37m179[0m.
+
+Here's a second example:
+
+<x=-8, y=-10, z=0>
+<x=5, y=5, z=10>
+<x=2, y=-7, z=3>
+<x=9, y=-8, z=-3>
+
+Every ten steps of simulation for 100 steps produces:
+
+After 0 steps:
+pos=<x= -8, y=-10, z= 0>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 5, y= 5, z= 10>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 2, y= -7, z= 3>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 9, y= -8, z= -3>, vel=<x= 0, y= 0, z= 0>
+
+After 10 steps:
+pos=<x= -9, y=-10, z= 1>, vel=<x= -2, y= -2, z= -1>
+pos=<x= 4, y= 10, z= 9>, vel=<x= -3, y= 7, z= -2>
+pos=<x= 8, y=-10, z= -3>, vel=<x= 5, y= -1, z= -2>
+pos=<x= 5, y=-10, z= 3>, vel=<x= 0, y= -4, z= 5>
+
+After 20 steps:
+pos=<x=-10, y= 3, z= -4>, vel=<x= -5, y= 2, z= 0>
+pos=<x= 5, y=-25, z= 6>, vel=<x= 1, y= 1, z= -4>
+pos=<x= 13, y= 1, z= 1>, vel=<x= 5, y= -2, z= 2>
+pos=<x= 0, y= 1, z= 7>, vel=<x= -1, y= -1, z= 2>
+
+After 30 steps:
+pos=<x= 15, y= -6, z= -9>, vel=<x= -5, y= 4, z= 0>
+pos=<x= -4, y=-11, z= 3>, vel=<x= -3, y=-10, z= 0>
+pos=<x= 0, y= -1, z= 11>, vel=<x= 7, y= 4, z= 3>
+pos=<x= -3, y= -2, z= 5>, vel=<x= 1, y= 2, z= -3>
+
+After 40 steps:
+pos=<x= 14, y=-12, z= -4>, vel=<x= 11, y= 3, z= 0>
+pos=<x= -1, y= 18, z= 8>, vel=<x= -5, y= 2, z= 3>
+pos=<x= -5, y=-14, z= 8>, vel=<x= 1, y= -2, z= 0>
+pos=<x= 0, y=-12, z= -2>, vel=<x= -7, y= -3, z= -3>
+
+After 50 steps:
+pos=<x=-23, y= 4, z= 1>, vel=<x= -7, y= -1, z= 2>
+pos=<x= 20, y=-31, z= 13>, vel=<x= 5, y= 3, z= 4>
+pos=<x= -4, y= 6, z= 1>, vel=<x= -1, y= 1, z= -3>
+pos=<x= 15, y= 1, z= -5>, vel=<x= 3, y= -3, z= -3>
+
+After 60 steps:
+pos=<x= 36, y=-10, z= 6>, vel=<x= 5, y= 0, z= 3>
+pos=<x=-18, y= 10, z= 9>, vel=<x= -3, y= -7, z= 5>
+pos=<x= 8, y=-12, z= -3>, vel=<x= -2, y= 1, z= -7>
+pos=<x=-18, y= -8, z= -2>, vel=<x= 0, y= 6, z= -1>
+
+After 70 steps:
+pos=<x=-33, y= -6, z= 5>, vel=<x= -5, y= -4, z= 7>
+pos=<x= 13, y= -9, z= 2>, vel=<x= -2, y= 11, z= 3>
+pos=<x= 11, y= -8, z= 2>, vel=<x= 8, y= -6, z= -7>
+pos=<x= 17, y= 3, z= 1>, vel=<x= -1, y= -1, z= -3>
+
+After 80 steps:
+pos=<x= 30, y= -8, z= 3>, vel=<x= 3, y= 3, z= 0>
+pos=<x= -2, y= -4, z= 0>, vel=<x= 4, y=-13, z= 2>
+pos=<x=-18, y= -7, z= 15>, vel=<x= -8, y= 2, z= -2>
+pos=<x= -2, y= -1, z= -8>, vel=<x= 1, y= 8, z= 0>
+
+After 90 steps:
+pos=<x=-25, y= -1, z= 4>, vel=<x= 1, y= -3, z= 4>
+pos=<x= 2, y= -9, z= 0>, vel=<x= -3, y= 13, z= -1>
+pos=<x= 32, y= -8, z= 14>, vel=<x= 5, y= -4, z= 6>
+pos=<x= -1, y= -2, z= -8>, vel=<x= -3, y= -6, z= -9>
+
+After 100 steps:
+pos=<x= 8, y=-12, z= -9>, vel=<x= -7, y= 3, z= 0>
+pos=<x= 13, y= 16, z= -3>, vel=<x= 3, y=-11, z= -5>
+pos=<x=-29, y=-11, z= -1>, vel=<x= -3, y= 7, z= 4>
+pos=<x= 16, y=-13, z= 23>, vel=<x= 7, y= 1, z= 1>
+
+Energy after 100 steps:
+pot: 8 + 12 + 9 = 29; kin: 7 + 3 + 0 = 10; total: 29 * 10 = 290
+pot: 13 + 16 + 3 = 32; kin: 3 + 11 + 5 = 19; total: 32 * 19 = 608
+pot: 29 + 11 + 1 = 41; kin: 3 + 7 + 4 = 14; total: 41 * 14 = 574
+pot: 16 + 13 + 23 = 52; kin: 7 + 1 + 1 = 9; total: 52 * 9 = 468
+Sum of total energy: 290 + 608 + 574 + 468 = [1m[37m1940[0m
+
+[1m[37mWhat is the total energy in the system[0m after simulating the moons given in your scan
+for 1000 steps?
+
+
diff --git a/src/12/part2 b/src/12/part2
@@ -0,0 +1,50 @@
+--- Part Two ---
+
+All this drifting around in space makes you wonder about the nature of the universe. Does history
+really repeat itself? You're curious whether the moons will ever return to a previous state.
+
+Determine [1m[37mthe number of steps[0m that must occur before all of the moons'
+[1m[37mpositions and velocities[0m exactly match a previous point in time.
+
+For example, the first example above takes 2772 steps before they exactly match a previous point in
+time; it eventually returns to the initial state:
+
+After 0 steps:
+pos=<x= -1, y= 0, z= 2>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 2, y=-10, z= -7>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 4, y= -8, z= 8>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 3, y= 5, z= -1>, vel=<x= 0, y= 0, z= 0>
+
+After 2770 steps:
+pos=<x= 2, y= -1, z= 1>, vel=<x= -3, y= 2, z= 2>
+pos=<x= 3, y= -7, z= -4>, vel=<x= 2, y= -5, z= -6>
+pos=<x= 1, y= -7, z= 5>, vel=<x= 0, y= -3, z= 6>
+pos=<x= 2, y= 2, z= 0>, vel=<x= 1, y= 6, z= -2>
+
+After 2771 steps:
+pos=<x= -1, y= 0, z= 2>, vel=<x= -3, y= 1, z= 1>
+pos=<x= 2, y=-10, z= -7>, vel=<x= -1, y= -3, z= -3>
+pos=<x= 4, y= -8, z= 8>, vel=<x= 3, y= -1, z= 3>
+pos=<x= 3, y= 5, z= -1>, vel=<x= 1, y= 3, z= -1>
+
+After 2772 steps:
+pos=<x= -1, y= 0, z= 2>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 2, y=-10, z= -7>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 4, y= -8, z= 8>, vel=<x= 0, y= 0, z= 0>
+pos=<x= 3, y= 5, z= -1>, vel=<x= 0, y= 0, z= 0>
+
+Of course, the universe might last for a [1m[37mvery long time[0m before repeating. Here's a
+copy of the second example from above:
+
+<x=-8, y=-10, z=0>
+<x=5, y=5, z=10>
+<x=2, y=-7, z=3>
+<x=9, y=-8, z=-3>
+
+This set of initial positions takes 4686774924 steps before it repeats a previous state! Clearly,
+you might need to [1m[37mfind a more efficient way to simulate the universe[0m.
+
+[1m[37mHow many steps does it take[0m to reach the first state that exactly matches a previous
+state?
+
+
diff --git a/src/12/test.input b/src/12/test.input
@@ -0,0 +1,4 @@
+<x=-8, y=-10, z=0>
+<x=5, y=5, z=10>
+<x=2, y=-7, z=3>
+<x=9, y=-8, z=-3>
diff --git a/src/12/test.input2 b/src/12/test.input2
@@ -0,0 +1,4 @@
+<x=-1, y=0, z=2>
+<x=2, y=-10, z=-7>
+<x=4, y=-8, z=8>
+<x=3, y=5, z=-1>
