|
| 1 | +// https://leetcode.com/problems/design-underground-system/ |
| 2 | +classUndergroundSystem{ |
| 3 | +constructor(){ |
| 4 | +this.stationSystem={}; |
| 5 | +this.averageTime={}; |
| 6 | +} |
| 7 | + |
| 8 | +/** |
| 9 | + * Time O(1) | Space O(1) |
| 10 | + * Records the check-in time and station for a user. |
| 11 | + *@param {number} id - User ID |
| 12 | + *@param {string} stationName - Check-in station name |
| 13 | + *@param {number} t - Check-in time |
| 14 | + *@return {void} |
| 15 | + */ |
| 16 | +checkIn(id,stationName,t){ |
| 17 | +this.stationSystem[id]=[stationName,'',t,'']; |
| 18 | +} |
| 19 | + |
| 20 | +/** |
| 21 | + * Time O(1) | Space O(1) |
| 22 | + * Records the check-out time and station for a user, and calculates the average time. |
| 23 | + *@param {number} id - User ID |
| 24 | + *@param {string} stationName - Check-out station name |
| 25 | + *@param {number} t - Check-out time |
| 26 | + *@return {void} |
| 27 | + */ |
| 28 | +checkOut(id,stationName,t){ |
| 29 | +constuser=this.stationSystem[id]; |
| 30 | +user[1]=stationName; |
| 31 | +user[3]=t; |
| 32 | +conststationHash=`${user[0]}-${user[1]}`; |
| 33 | +if(this.averageTime[stationHash]){ |
| 34 | +this.averageTime[stationHash][0]+=1; |
| 35 | +this.averageTime[stationHash][1]+=user[3]-user[2]; |
| 36 | +}else{ |
| 37 | +this.averageTime[stationHash]=[]; |
| 38 | +this.averageTime[stationHash][0]=1; |
| 39 | +this.averageTime[stationHash][1]=user[3]-user[2]; |
| 40 | +} |
| 41 | +} |
| 42 | + |
| 43 | +/** |
| 44 | + * Time O(1) | Space O(1) |
| 45 | + * Returns the average time taken to travel between two stations. |
| 46 | + *@param {string} startStation - Start station name |
| 47 | + *@param {string} endStation - End station name |
| 48 | + *@return {number} - Average time in hours |
| 49 | + */ |
| 50 | +getAverageTime(startStation,endStation){ |
| 51 | +const[rounds,totalHours]=this.averageTime[`${startStation}-${endStation}`]; |
| 52 | +returntotalHours/rounds; |
| 53 | +} |
| 54 | +} |