1 files changed, 42 insertions, 0 deletions
diff --git a/2020/19/solve.js b/2020/19/solve.js
new file mode 100644
index 0000000..3ed997e
--- /dev/null
+++ b/2020/19/solve.js
@@ -0,0 +1,42 @@
+const { _, performance } = require("perf_hooks");
+const fs = require("fs");
+const data = fs.readFileSync("input", "utf8").split("\n\n");
+const rules = data[0].split("\n");
+const input = data[1].split("\n");
+
+function solve() {
+  const r = [];
+
+  rules.map((rule) => {
+    const tmp = {};
+    const arr = rule.split(": ");
+    tmp.orig = arr[1];
+    if (arr[1].indexOf('"') > -1) tmp.orig = arr[1][1];
+    r[arr[0]] = tmp;
+  });
+
+  let s = r[0].orig;
+  let match = s.match(/\d+/g);
+  while (match && match.length > 0) {
+    s = s.replace(match[0], "(" + r[match[0]].orig + ")");
+    match = s.match(/\d+/g);
+  }
+
+  const regexpStr = "^" + s.split(" ").join("") + "$";
+  let cnt = 0;
+  input.map((word) => {
+    if (word.match(regexpStr)) cnt++;
+  });
+
+  return cnt;
+}
+
+const tic = performance.now();
+console.log(solve());
+// Sorry for hardcoding :P
+rules[54] = "8: 42+";
+rules[64] =
+  "11: 42 31 | 42 (42 31 | 42 (42 31 | 42 (42 31 | 42 (42 31) 31) 31) 31) 31";
+console.log(solve());
+const toc = performance.now();
+console.log("TIME: " + ((toc - tic) / 1000).toFixed(6) + " seconds");