From 91ec1be6231ffa1caa8fb30c901b352b36e6898a Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Sat, 5 Dec 2020 13:07:08 +0100
Subject: [PATCH] Add 2020 day 4

---
 2020/day4/day4.js | 60 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100755 2020/day4/day4.js

diff --git a/2020/day4/day4.js b/2020/day4/day4.js
new file mode 100755
index 0000000..3e3c0d8
--- /dev/null
+++ b/2020/day4/day4.js
@@ -0,0 +1,60 @@
+#!/bin/node
+
+const fs = require('fs');
+
+fs.readFile('input.txt', (err, data) => {
+    const passports = [];
+    data.toString()
+        .split('\n\n')
+        .map(line => line.replaceAll('\n', ' '))
+        .map((line, index) => line.split(' ').map(f => {
+            if (!passports[index]) passports[index] = {};
+            const [key, value] = f.split(':');
+            passports[index][key] = value;
+        }));
+
+    const requiredFields = [
+        ['byr', v => {
+            const number = Number(v);
+            return v.length === 4 && number >= 1920 && number <= 2002;
+        }],
+        ['iyr', v => {
+            const number = Number(v);
+            return v.length === 4 && number >= 2010 && number <= 2020;
+        }],
+        ['eyr', v => {
+            const number = Number(v);
+            return v.length === 4 && number >= 2020 && number <= 2030;
+        }],
+        ['hgt', v => {
+            const n = Number(v.substring(0, v.length - 2));
+            if (v.endsWith('cm')) return n >= 150 && n <= 193;
+            else if (v.endsWith('in')) return n >= 59 && n <= 76;
+            else return false;
+        }],
+        ['hcl', v => /^#[0-9a-f]{6}$/.test(v)],
+        ['ecl', v => /^(amb|blu|brn|gry|grn|hzl|oth)$/.test(v)],
+        ['pid', v => /^[0-9]{9}$/.test(v)],
+    ];
+
+    let q1 = 0, q2 = 0;
+    for (const passport of passports) {
+        console.log(passport);
+
+        let q1Fields = 0, q2Fields = 0;
+        for (const [fieldName, validator] of requiredFields) {
+            if (Object.keys(passport).indexOf(fieldName) >= 0) {
+                q1Fields++;
+
+                if (validator(passport[fieldName])) q2Fields++;
+                console.log('>', fieldName, passport[fieldName], validator(passport[fieldName]));
+            }
+        }
+        console.log('>', q1Fields + '/' + requiredFields.length, q2Fields + '/' + requiredFields.length);
+
+        if (q1Fields === requiredFields.length) q1++;
+        if (q2Fields === requiredFields.length) q2++;
+    }
+
+    console.log(q1 + '/' + passports.length, q2 + '/' + passports.length);
+});