advent2022/d18/main.js

const fs = require('fs');
const readline = require('readline');

Array.prototype.count = function(fnc) {
    return this.reduce((total, i, index) => fnc(i, index) ? total+1 : total, 0);
}

Array.prototype.countUnique = function(fnc) {
    return this.reduce((total, i, index) => (total.indexOf(i) === -1 && fnc(i, index)) ? total.concat(i):total, []).length;
}

function getAdjascents(pos) {
    return [
        [ pos.coords[0] -1, pos.coords[1], pos.coords[2] ],
        [ pos.coords[0] +1, pos.coords[1], pos.coords[2] ],
        [ pos.coords[0], pos.coords[1] +1, pos.coords[2] ],
        [ pos.coords[0], pos.coords[1] -1, pos.coords[2] ],
        [ pos.coords[0], pos.coords[1], pos.coords[2] +1 ],
        [ pos.coords[0], pos.coords[1], pos.coords[2] -1 ]
    ];
}

function countShards(map) {
    return Object.keys(map).reduce((acc, i) => acc +getAdjascents(map[i]).map(i => i.join(',')).count(i => !map[i]), 0);
}

function isTrapped(map, arr, obj) {
    // FIXME
    return false;
}

function countShards2(map) {
    const keys = Object.keys(map);
    if (keys.length < 8) return countShards(map); // trivial out
    return Object.keys(map).reduce((acc, i) => acc +getAdjascents(map[i]).map(i => i.join(',')).count(i => !map[i] && !isTrapped(map, i)), 0);
}

function manhatan(a, b) {
    return a.reduce((acc, val, index) => acc + Math.abs(b[index]-val), 0);
}

function mergeIds(map, oldId, newId) {
    Object.keys(map).forEach(i => { if (map[i].gid === oldId) map[i].gid = newId;});
}

function computeShardShape(map) {
    const keys = Object.keys(map);
    let ids = [];
    let maxId = 0;
    for (let i =0; i < keys.length; ++i) {
        if (map[keys[i]].gid !== undefined) {
            for (let j = 0; j < i; ++j) {
                if (map[keys[i]].gid !== map[keys[j]].gid && manhatan(map[keys[i]].coords, map[keys[j]].coords) === 1)
                    mergeIds(map, map[keys[i]].gid, map[keys[j]].gid);
            }
            continue;
        }
        map[keys[i]].gid = ++maxId;
        ids.push(maxId);
        for (let j = 1; j < keys.length; ++j)
            if (manhatan(map[keys[i]].coords, map[keys[j]].coords) === 1) {
                if (map[keys[j]].gid !== undefined)
                    mergeIds(map, maxId, map[keys[j]].gid);
                else
                    map[keys[j]].gid = maxId;
            }
    }
    return ids.map(i => keys.filter(j => i === map[j].gid).map(i => map[i])).filter(i => i.length).map(i => i.reduce((acc, i) => { acc[i.id] = i; return acc; }, {}));
}

async function main() {
    let shards = {};
    for await (let line of readline.createInterface({ input: process.stdin })) {
        shards[line] = {
            coords: line.split(',').map(i => parseInt(i)),
            gid: undefined,
            id: line
        }
    }
    let extShards = countShards(shards);
    console.log(extShards);
    //console.log(require('util').inspect(computeShardShape(shards), { showHidden: false, depth: null, colors: true }));
    console.log(computeShardShape(shards).reduce((acc, i) => countShards2(i)+acc, 0));
};

(main());