AoC 2022, part2

part2.js

const fs = require("fs");
const content = fs.readFileSync("input").toString().split("\n").map(i => i.split(''));
content.pop();
let routes = [];
let starts = [];
end = {
    i: 0,
    j: 0
};
for (let i = 0; i < content.length; i++) {
    for (let j = 0; j < content[i].length; j++) {
        if (content[i][j] == 'S') {
            content[i][j] = 'a'
        }
        if (content[i][j] == 'E') {
            content[i][j] = 'z'
            end = {
                i: i,
                j: j
            };
        }
        if (content[i][j] == 'a') {
            starts.push(i + ':' + j);
        }
        let r = []
        if (content[i - 1] !== undefined && content[i - 1][j].charCodeAt(0) <= (content[i][j].charCodeAt(0) + 1)) {
            r.push((i - 1) + ':' + j);
        }
        if (content[i][j + 1] !== undefined && content[i][j + 1].charCodeAt(0) <= (content[i][j].charCodeAt(0) + 1)) {
            r.push(i + ':' + (j + 1));
        }
        if (content[i + 1] !== undefined && content[i + 1][j].charCodeAt(0) <= (content[i][j].charCodeAt(0) + 1)) {
            r.push((i + 1) + ':' + j);
        }
        if (content[i][j - 1] !== undefined && content[i][j - 1].charCodeAt(0) <= (content[i][j].charCodeAt(0) + 1)) {
            r.push(i + ':' + (j - 1));
        }
        routes[i + ':' + j] = r;
    }
}
shortest = 10000;
starts.forEach(s => {
    paths = [
        [s]
    ];
    r = Object.assign({}, routes);
    while (paths.length) {
        item = paths.shift();
        let last_item = item.pop()
        if (end.i == last_item.split(':')[0] && end.j == last_item.split(':')[1]) {
            if (item.length < shortest) shortest = item.length;
        }
        if (r[last_item] !== undefined) {
            r[last_item].forEach(x => {
                paths.push([...item, last_item, x])
            })
            delete r[last_item]
        }
    }
});

console.log(shortest)