TimeTravelTime

function solve(arr) {
    const countries = new Map();

    for(let line of arr) {
        let [country, city, price] = line.split(' > ');
        if(!countries.has(country)) {
            let obj = {
                [city]: Number(price),
            }

            countries.set(country, obj);
        } else {
            if(countries.get(country)[city] != undefined) {
                let oldPrice = countries.get(country)[city];
                if(price < oldPrice) {
                    countries.get(country)[city] = price;
                }
            } else {
                countries.get(country)[city] = price;
            }
        }
    }

    let sortedEntries = Array.from(countries.entries()).sort();

    sortedEntries.forEach(entrie => {
        let [country, obj] = entrie;
        let objectEntries = Object.entries(obj);

        if(objectEntries.length > 1) {
            objectEntries = objectEntries.sort((a, b) => {
                costA = a[1];
                costB = b[1];

                return costA - costB;
            });

            let resultString = '';

            objectEntries.forEach(city => {
                let str = (city.join(' -> '));
                resultString += str + ' ';
            });

            console.log(`${country} -> ${resultString}`);
        } else {
            let str = objectEntries[0].join(' -> ');
            console.log(`${country} -> ${str}`);
        }
    });
}