Add day 6 part 2

Author: lundgren2

src/2020/day6/part2.ts

@@ -0,0 +1,12 @@
+export const part2 = (input: string) => {
+  return input.split('\n\n').reduce((sum, group) => {
+    const groupSize = group.split('\n').length;
+    const allVotes = group.replace(/(\n|\s\r)/g, '');
+    const uniqueVotes = new Set(allVotes);
+    const voteCount = [...uniqueVotes].reduce((a, vote) => {
+      return a + Number(allVotes.split(vote).length - 1 === groupSize);
+    }, 0);
+
+    return sum + voteCount;
+  }, 0);
+};

src/2020/day6/test.spec.ts

@@ -1,35 +1,32 @@
 import {part1} from './part1';
+import {part2} from './part2';
 import {readInput} from '../../utils';
 
 describe('Advent of Code 2020 - Day 6', () => {
+  let testInput: string;
   let input: string;
   beforeAll(async () => {
+    testInput = await readInput(__dirname + '/test_input');
     input = await readInput(__dirname + '/input');
   });
 
   describe('part 1', () => {
     it('should output 11 for test input', () => {
-      const input = `abc
-
-a
-b
-c
-
-ab
-ac
+      expect(part1(testInput)).toBe(11);
+    });
 
-a
-a
-a
-a
+    it('should output 6161 from input', () => {
+      expect(part1(input)).toBe(6161);
+    });
+  });
 
-b
-`;
-      expect(part1(input)).toBe(11);
+  describe('part 2', () => {
+    it('should output 6 for test input', () => {
+      expect(part2(testInput)).toBe(6);
     });
 
     it('should output 6161 from input', () => {
-      expect(part1(input)).toBe(6161);
+      expect(part2(input)).toBe(2971);
     });
   });
 });

src/2020/day6/test_input

@@ -0,0 +1,15 @@
+abc
+
+a
+b
+c
+
+ab
+ac
+
+a
+a
+a
+a
+
+b