|
| 1 | + |
| 2 | +const UndergroundSystem = function() { |
| 3 | + this.h = new Map() |
| 4 | + this.routeMap = new Map() |
| 5 | +}; |
| 6 | + |
| 7 | +/** |
| 8 | + * @param {number} id |
| 9 | + * @param {string} stationName |
| 10 | + * @param {number} t |
| 11 | + * @return {void} |
| 12 | + */ |
| 13 | +UndergroundSystem.prototype.checkIn = function(id, stationName, t) { |
| 14 | + this.h.set(id, [stationName, t]) |
| 15 | +}; |
| 16 | + |
| 17 | +/** |
| 18 | + * @param {number} id |
| 19 | + * @param {string} stationName |
| 20 | + * @param {number} t |
| 21 | + * @return {void} |
| 22 | + */ |
| 23 | +UndergroundSystem.prototype.checkOut = function(id, stationName, t) { |
| 24 | + const [sn, st] = this.h.get(id) |
| 25 | + this.h.delete(id) |
| 26 | + const route = `${sn},${stationName}` |
| 27 | + const duration = t - st |
| 28 | + const [totalTime, totalValue] = this.routeMap.get(route) || ([0, 0]) |
| 29 | + this.routeMap.set(route, [totalTime + duration, totalValue + 1]) |
| 30 | +}; |
| 31 | + |
| 32 | +/** |
| 33 | + * @param {string} startStation |
| 34 | + * @param {string} endStation |
| 35 | + * @return {number} |
| 36 | + */ |
| 37 | +UndergroundSystem.prototype.getAverageTime = function(startStation, endStation) { |
| 38 | + const k = `${startStation},${endStation}` |
| 39 | + const [time, number] = this.routeMap.get(k) |
| 40 | + return time / number |
| 41 | +}; |
| 42 | + |
| 43 | +/** |
| 44 | + * Your UndergroundSystem object will be instantiated and called as such: |
| 45 | + * var obj = new UndergroundSystem() |
| 46 | + * obj.checkIn(id,stationName,t) |
| 47 | + * obj.checkOut(id,stationName,t) |
| 48 | + * var param_3 = obj.getAverageTime(startStation,endStation) |
| 49 | + */ |
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