1 files changed, 32 insertions, 0 deletions
diff --git a/day21/day21-1.js b/day21/day21-1.js
new file mode 100644
index 0000000..08ddc95
--- /dev/null
+++ b/day21/day21-1.js
@@ -0,0 +1,32 @@
+const data = require('./data')
+let arr = data
+  .split(/\n/g).filter(Boolean)
+  .map(l => l.replace(')','').split(' (contains '))
+  .map(l => [l[0].split(' '), l[1].split(', ')])
+
+const ingredients = {}
+const allergens = {}
+
+for (let i=0; i<arr.length; i++) {
+  for (let j=0; j<arr[i][0].length; j++) {
+    let ingredient = arr[i][0][j]
+    if (!ingredients[ingredient]) { ingredients[ingredient] = [] }
+    ingredients[ingredient].push(i)
+  }
+  for (let k=0; k<arr[i][1].length; k++) {
+    let allergen = arr[i][1][k]
+    if (!allergens[allergen]) { allergens[allergen] = [] }
+    allergens[allergen].push(i)
+  }
+}
+
+Object.values(allergens).forEach(allergen => {
+  Object.entries(ingredients).forEach(ingredient => {
+    if(allergen.every(a => ingredient[1].includes(a))) {
+      delete ingredients[ingredient[0]]
+    }
+  })
+})
+
+const answer = Object.values(ingredients).map(i => i.length).reduce((a, b) => a + b, 0)
+console.log('Answer: ', answer)