1 files changed, 56 insertions, 0 deletions
diff --git a/day16/day16-2.js b/day16/day16-2.js
new file mode 100644
index 0000000..e24435a
--- /dev/null
+++ b/day16/day16-2.js
@@ -0,0 +1,56 @@
+const data = require('./data')
+const ranges = data
+  .split('\nyour ticket:')[0]
+  .split(/\n/g)
+  .filter(r => r)
+  .map(r => ({[r.split(': ')[0]]: r.split(': ')[1].split(' or ').map(s => s.split('-').map(a => parseInt(a)))}))
+  .reduce((c, n) => ({ ...c, ...n}), {})
+
+const your = data
+  .split('your ticket:\n')[1]
+  .split('nearby tickets:\n')[0]
+  .split(',')
+  .map(n => parseInt(n.replace(/\n/g,'')))
+
+const nearby = data
+  .split('nearby tickets:\n')[1]
+  .split(/\n/g)
+  .filter(n => n)
+  .map(n => n.split(',').map(nr => parseInt(nr)))
+  .filter(n => n.every(nr => Object.values(ranges).some(r => r.some(ra => nr >= ra[0] && nr <= ra[1] ))))
+
+const nearbyColumns = Array(nearby[0].length).fill([])
+nearby.forEach((n) => {
+  n.forEach((num, i) => {
+    nearbyColumns[i] = [ ...nearbyColumns[i], num]
+  })
+})
+
+const ids = {}
+const keys = Object.keys(ranges)
+keys.forEach(key => {
+  ids[key] = []
+  nearbyColumns.filter((col, id) => {
+    const check = col.every(n => ranges[key].some(r => n >= r[0] && n <= r[1]))
+    if (check) { ids[key].push(id)  }
+    return check
+  })
+});
+
+const simplify = (arr) => {
+  if (arr.every(a => a.length === 1)) {
+    return arr
+  } else {
+    const singles = arr.filter(a => a.length === 1).map(a => a[0])
+    const newArr = arr.map(a => a.filter(n => !singles.includes(n) || a.length === 1))
+    return simplify(newArr)
+  }
+}
+
+const result = simplify(Object.values(ids))
+  .filter((v,i) => Object.keys(ids)[i].startsWith('departure'))
+  .map(d => your[d[0]])
+  .reduce((a,b) => a * b, 1)
+
+console.log('Answer: ', result)
+