adventofcode/2021/08/part2.mjs
2021-12-08 12:45:55 -05:00

123 lines
3.1 KiB
JavaScript

import fs from "fs-extra";
import fp from "lodash/fp.js";
import _ from "lodash";
import * as p1 from './part1.mjs';
function decodedDigits(mapping) {
const s = fp.invert(mapping);
let solution = fp.invert(p1.digits);
solution = fp.mapKeys(
k => k.split('').map(
l => s[l]
).join('')
,solution );
solution = fp.mapKeys( k => { k = k.split('').sort().join(''); return k }, solution );
return solution;
}
function guess(unknowns,guessed={},inputs) {
console.log({unknowns,guessed});
const [ next ] = Object.keys(unknowns);
if(!next) return guessed;
if(unknowns[next].size === 0) return;
for ( const p of unknowns[next].values() ) {
let newUnknowns = fp.omit(next, unknowns);
newUnknowns = fp.mapValues(
s => {
const x = new Set(s.values());
x.delete(p);
return x;
}, newUnknowns );
//console.log({ newUnknowns })
if(
Object.values(newUnknowns).some( s => s.size === 0 )
) continue;
const r = guess( newUnknowns, { ...guessed, [next]: p }, inputs );
if(r) {
const s = fp.invert(r);
let solution = fp.invert(p1.digits);
solution = fp.mapKeys(
k => k.split('').map(
l => s[l]
).join('')
,solution );
solution = fp.mapKeys( k => { k = k.split('').sort().join(''); return k }, solution );
console.log({r, solution });
console.log({inputs})
if( inputs.some( i => ! solution.hasOwnProperty(i.join('')) ) ) {
console.log("Oh noes");
} else {
console.log("Oh yea");
return r;
}
}
}
}
export function findMapping(input) {
const values = 'abcdefg'.split('');
const possibility = Object.fromEntries(values.map(
v => [ v, new Set(values) ]
));
for ( const seq of input ) {
const p = Object.values(p1.digits).filter(
d => d.length === seq.length
).join('').split('');
for( const l of seq ) {
possibility[l] = new Set(
p.filter( x => possibility[l].has(x) )
);
}
// console.log(possibility);
}
const one = input.find( i => i.length === 2 );
const seven = input.find( i => i.length === 3 );
const [a] = seven.filter( x => !one.includes(x) );
for( const l of Object.values(possibility) ) {
l.delete('a');
}
possibility[a] = new Set(['a']);
console.log(possibility);
return guess(possibility,{},input);
}
export function decodedOutput({input,output}) {
const mapping = findMapping([...input,...output]);
const digits = decodedDigits(mapping);
console.log({ digits, output });
return parseInt(output.map( e => digits[e.join('')] ).join(''));
}
export function solution(input) {
return _.sum( input.map( decodedOutput ) );
}