https://leetcode.com/problems/cheapest-flights-within-k-stops/description/?envType=daily-question&envId=2024-02-23

var findCheapestPrice = function(n, flights, src, dst, K) {
    const adjacencyList = new Map();

    for(let [start, end, cost] of flights) {
        if(adjacencyList.has(start)) adjacencyList.get(start).push([end, cost]);
        else adjacencyList.set(start, [[end, cost]]);
    }

    const queue = [[0, src, K+1]];
    const visited = new Map();

    while(queue.length) {
        queue.sort((a, b) => a[0] - b[0]);

        const [cost, city, stops] = queue.shift();
        visited.set(city, stops);

        if(city === dst) return cost;
        if(stops <= 0 || !adjacencyList.has(city))  continue;

        for(let [nextCity, nextCost] of adjacencyList.get(city)) {
            if(visited.has(nextCity) && visited.get(nextCity) >= stops-1) continue;
            queue.push([cost+nextCost, nextCity, stops-1]);
        }
    }
    return -1;
};