// Найти непокрытые штаты
// Выбрать странцию покрывающую больше всех штатов из непокрытых

const findStations = (allStationLst, needStateList) => {
  let needed = new Set([...needStateList]);
  let result = new Set();

  while (needed.size > 0) {
    let statesCovered = new Set();
    let stationCandidate;

    Object.keys(allStationLst).forEach((station) => {
      const stationStateCovered = new Set([...allStationLst[station]].filter(item => needed.has(item)));
      if (stationStateCovered.size > statesCovered.size) {
        statesCovered = stationStateCovered;
        stationCandidate = station;
      }
    })

    result.add(stationCandidate);
    needed = new Set([...needed].filter(item => !statesCovered.has(item)));
  }

  return result
};

const needStateList = new Set(["mt", "wa", "or", "id", "nv", "ut", "ca", "az"]);
const stations = {
    kone: new Set(["id", "nv", "ut"]),
    ktwo: new Set(["wa", "id", "mt"]),
    kthree: new Set(["or", "nv", "ca"]),
    kfour: new Set(["nv", "ut"]),
    kfive: new Set(["ca", "az"]),
};


console.log(findStations(stations, needStateList));