day18

1 files changed, 29 insertions, 0 deletions

diff --git a/day18/day18-2.js b/day18/day18-2.js
new file mode 100644
index 0000000..d6f6e58
--- /dev/null
+++ b/day18/day18-2.js
@@ -0,0 +1,29 @@
+const data = require('./data')
+const lines = data.split(/\n/g).filter(Boolean)
+
+const ev = (str) => {
+  let spl = str.split(' ')
+  while(spl.length) {
+    spl = [eval(spl.slice(0, 3).join(''))].concat(spl.slice(3))
+  }
+  return spl[0]
+}
+
+const evPlus = (str) => {
+  while (/\+/.test(str)) {
+    str = str.replace(/(\d+) \+ (\d+)/g, (match, n1, n2) => parseInt(n1) + parseInt(n2))
+  }
+  return eval(str)
+}
+
+const evPar = (str, ev) => {
+  while(/\(/.test(str)) {
+    str = str.replace(/\(([^()]+)\)/g, (match, par) => ev(par))
+  }
+  return ev(str)
+}
+
+let sum = 0
+lines.forEach(l => sum += evPar(l, evPlus))
+console.log('Answer: ', sum)
+