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 (1983B)

      1 #!/usr/bin/env node
      2 
      3 const fs = require('node:fs');
      4 
      5 String.prototype.splice = function (start, deleteCount, ...newElements) {
      6   return this.slice(0, start) + `${(newElements||[]).join('')}` + this.slice(start + deleteCount);
      7 }
      8 
      9 const input = fs
     10   .readFileSync('input', 'utf-8')
     11   .split('\r\n').join('\n')
     12   .split('\r').join('\n')
     13   .split('\n')
     14   .filter(e => e)
     15 
     16 // Copy & turn into character array
     17 const part1map = [
     18   ...input.map(line => line.split(''))
     19 ];
     20 
     21 // Copy & turn into character array
     22 const part2map = [
     23   ...input.map(line => line
     24     .split('')
     25     .map(char => char === 'S' ? 1 : 0)
     26   )
     27 ];
     28 
     29 let totalSplits = 0;
     30 
     31 for(let lineIdx = 1 ; lineIdx < part1map.length ; lineIdx++) {
     32   for(let charIdx = 0 ; charIdx < part1map[lineIdx].length ; charIdx++) {
     33 
     34     switch(`${part1map[lineIdx-1][charIdx]}${part1map[lineIdx][charIdx]}`) {
     35       case 'S.':
     36       case '|.':
     37       case '||':
     38         part1map[lineIdx][charIdx]  = '|';
     39         part2map[lineIdx][charIdx] += part2map[lineIdx-1][charIdx];
     40         break;
     41       case '|^':
     42         part1map[lineIdx][charIdx-1] = '|';
     43         part1map[lineIdx][charIdx+1] = '|';
     44         part2map[lineIdx][charIdx-1] += part2map[lineIdx-1][charIdx];
     45         part2map[lineIdx][charIdx+1] += part2map[lineIdx-1][charIdx];
     46         totalSplits++;
     47         break;
     48       case '^.':
     49       case '.^':
     50       case '.|':
     51       case '..':
     52         // Intentionally empty
     53         break;
     54       default:
     55         throw new Error(`Unhandled case: ${part1map[lineIdx-1][charIdx]}${part1map[lineIdx][charIdx]}`);
     56     }
     57 
     58   }
     59 }
     60 
     61 const part1 = totalSplits;
     62 console.log(`${part1map.map(line => line.join('')).join('\n')}`);
     63 console.log(`${part2map.map(line => line.map(n => n.toString(36)).join('')).join('\n')}`);
     64 
     65 const timelines = part2map.slice(-1)[0].reduce((r,a)=>r+a,0);
     66 const part2     = timelines;
     67 
     68 process.stdout.write(`\n\n`);
     69 process.stdout.write(`------[ Part 1: ${part1} ]------\n`);
     70 process.stdout.write(`------[ Part 2: ${part2} ]------\n`);