advent-of-code

Entries to advent of code, multiple years
git clone git://git.finwo.net/misc/advent-of-code
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index.js (2307B)

      1 const fs           = require('fs');
      2 const through      = require('through2');
      3 const by_paragraph = require('../common/by-paragraph');
      4 const line_by_line = require('../common/line-for-line');
      5 
      6 String.prototype.startsWith = function(subject) {
      7   return this.substr(0, subject.length) === subject;
      8 };
      9 
     10 function verify(left, right) {
     11   // If both values are 
     12   if (
     13     ('number' === typeof left) &&
     14     ('number' === typeof right)
     15   ) {
     16     if (left < right) return true;
     17     if (left > right) return false;
     18   }
     19   // If both values are lists, compare values of each list
     20   if (
     21     Array.isArray(left) &&
     22     Array.isArray(right)
     23   ) {
     24     const len = Math.max(left.length, right.length);
     25     for(let i=0; i < len; i++) {
     26       if ('undefined' === typeof left[i]) return true;
     27       if ('undefined' === typeof right[i]) return false;
     28       const result = verify(left[i], right[i]);
     29       if ('boolean' === typeof result) return result;
     30     }
     31   }
     32   // If exactly one value is an int, convert the integer to a list and retry
     33   if (
     34     (Array.isArray(left)) &&
     35     ('number' === typeof right)
     36   ) {
     37     right = [right];
     38     return verify(left, right);
     39   }
     40   if (
     41     ('number' === typeof left) &&
     42     (Array.isArray(right))
     43   ) {
     44     left = [left];
     45     return verify(left, right);
     46   }
     47 }
     48 
     49 let   pairs    = 0;
     50 let   validSum = 0;
     51 const dividerA = [[2]];
     52 const dividerB = [[6]];
     53 const packets  = [
     54   dividerA,
     55   dividerB,
     56 ];
     57 
     58 fs.createReadStream('input')
     59   .pipe(by_paragraph())
     60 
     61   // Minor parsing
     62   .pipe(through.obj(function(paragraph, enc, cb) {
     63     paragraph = paragraph.toString();
     64     this.push(paragraph.split('\n').map(line => JSON.parse(line)));
     65     cb();
     66   }))
     67 
     68   .pipe(through.obj(function(pair, enc, cb) {
     69     const [left, right] = pair;
     70 
     71     const valid = verify(left, right);
     72     pairs++;
     73     if (valid) validSum += pairs;
     74 
     75     packets.push(left, right);
     76 
     77     console.log(left);
     78     console.log(right);
     79     console.log(valid);
     80     console.log('');
     81 
     82     cb();
     83   }))
     84 
     85   .on('finish', () => {
     86 
     87     packets.sort((left, right) => {
     88       return verify(left, right) ? -1 : 1;
     89     });
     90     const idxA = packets.indexOf(dividerA) + 1;
     91     const idxB = packets.indexOf(dividerB) + 1;
     92     const key  = idxA * idxB;
     93 
     94     console.log(packets);
     95     console.log({ validSum, key });
     96     console.log('finish');
     97   });