80 lines
2.5 KiB
Kotlin
80 lines
2.5 KiB
Kotlin
package assignment.week3.taxipark
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/*
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* Task #1. Find all the drivers who performed no trips.
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*/
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fun TaxiPark.findFakeDrivers(): Set<Driver> =
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this.allDrivers
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.filter { driver -> this.trips.none { trip -> trip.driver == driver } }
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.toSet()
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/*
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* Task #2. Find all the clients who completed at least the given number of trips.
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*/
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fun TaxiPark.findFaithfulPassengers(minTrips: Int): Set<Passenger> =
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this.allPassengers
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.filter { passenger -> this.trips.count { trip -> trip.passengers.contains(passenger) } >= minTrips }
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.toSet()
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/*
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* Task #3. Find all the passengers, who were taken by a given driver more than once.
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*/
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fun TaxiPark.findFrequentPassengers(driver: Driver): Set<Passenger> =
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this.allPassengers
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.filter { passenger ->
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this.trips
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.filter { trip -> trip.passengers.contains(passenger) }
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.count { trip -> trip.driver == driver } > 1
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}
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.toSet()
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/*
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* Task #4. Find the passengers who had a discount for majority of their trips.
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*/
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fun TaxiPark.findSmartPassengers(): Set<Passenger> = this.allPassengers
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.filter(fun(passenger: Passenger): Boolean {
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val (discounted, nonDiscounted) = this.trips
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.filter { it.passengers.contains(passenger) }
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.partition { it.discount != null }
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if (nonDiscounted.isEmpty()) {
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return discounted.isNotEmpty()
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}
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return (discounted.size.toDouble()) / nonDiscounted.size > 1.0
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})
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.toSet()
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/*
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* Task #5. Find the most frequent trip duration among minute periods 0..9, 10..19, 20..29, and so on.
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* Return any period if many are the most frequent, return `null` if there're no trips.
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*/
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fun TaxiPark.findTheMostFrequentTripDurationPeriod(): IntRange? {
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val (maxDuration, _) = this.trips
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.map { trip -> trip.duration / 10 }
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.groupBy { it }
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.maxByOrNull { it.value.size } ?: return null
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val startRange = maxDuration * 10
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return startRange.rangeTo(startRange + 9)
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}
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/*
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* Task #6.
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* Check whether 20% of the drivers contribute 80% of the income.
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*/
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fun TaxiPark.checkParetoPrinciple(): Boolean {
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if (this.trips.isEmpty()) {
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return false
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}
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val totalIncome = this.trips.sumOf(Trip::cost)
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val top20Percent = this.trips
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.groupBy { it.driver }
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.values
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.map { trips -> trips.sumOf(Trip::cost) }
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.sortedDescending()
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.take((this.allDrivers.size * 0.2).toInt())
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.sum()
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return top20Percent >= totalIncome * 0.8
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} |