Day 08 WIP

day08/part1.js

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+module.exports = (input) => {
+          let rows = input.split(/\r?\n/);
+          let instructions = [...rows[0]];
+
+          let tree = rows
+                    .slice(2)
+                    .map((r) => /([\w]+) = \(([\w]+), ([\w]+)\)/.exec(r))
+                    .map(([, a, l, r]) => [a, l, r])
+                    .reduce((map, [a, l, r]) => map.set(a, [l, r]), new Map());
+
+          let position = "AAA";
+          let ip = 0;
+          let length = 0;
+          while (position != "ZZZ") {
+                    position =
+                              tree.get(position)[
+                                        instructions[
+                                                  ip % instructions.length
+                                        ] == "L"
+                                                  ? 0
+                                                  : 1
+                              ];
+                    ip++;
+                    length++;
+          }
+          return length;
+};

day08/part2.js

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+function steps(tree, position) {}
+module.exports = (input) => {
+          let rows = input.split(/\r?\n/);
+          let instructions = [...rows[0]];
+
+          let tree = rows
+                    .slice(2)
+                    .map((r) => /([\w]+) = \(([\w]+), ([\w]+)\)/.exec(r))
+                    .map(([, a, l, r]) => [a, l, r])
+                    .reduce((map, [a, l, r]) => map.set(a, [l, r]), new Map());
+
+          let positions = [...tree.keys()].filter((a) => a.endsWith("A"));
+          let ip = 0;
+          let length = 0;
+          while (positions.some((e) => !e.endsWith("Z"))) {
+                    positions = positions.map(
+                              (position) =>
+                                        tree.get(position)[
+                                                  instructions[
+                                                            ip %
+                                                                      instructions.length
+                                                  ] == "L"
+                                                            ? 0
+                                                            : 1
+                                        ]
+                    );
+                    ip++;
+                    length++;
+          }
+          return length;
+};

day08/test.js

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+const expect = require("expect.js");
+const part1 = require("./part1");
+const part2 = require("./part2");
+
+describe("Day 08: Part 1", () => {
+          it("Should calculate number of steps required to finish", () => {
+                    expect(
+                              part1(`RL
+
+AAA = (BBB, CCC)
+BBB = (DDD, EEE)
+CCC = (ZZZ, GGG)
+DDD = (DDD, DDD)
+EEE = (EEE, EEE)
+GGG = (GGG, GGG)
+ZZZ = (ZZZ, ZZZ)`)
+                    ).to.equal(2);
+
+                    expect(
+                              part1(`LLR
+
+AAA = (BBB, BBB)
+BBB = (AAA, ZZZ)
+ZZZ = (ZZZ, ZZZ)`)
+                    ).to.equal(6);
+          });
+});
+describe("Day 08: Part 2", () => {
+          it("Should calculate number of steps required to finish all paths starting with A simultaniously", () => {
+                    expect(
+                              part2(`LR
+
+11A = (11B, XXX)
+11B = (XXX, 11Z)
+11Z = (11B, XXX)
+22A = (22B, XXX)
+22B = (22C, 22C)
+22C = (22Z, 22Z)
+22Z = (22B, 22B)
+XXX = (XXX, XXX)`)
+                    ).to.equal(6);
+          });
+});