enough_water_for_how_many_days.js

// Description:
//     Hello dweller,
//
//     I'm the overseer of our vault, in which we all live.
//
// I make it short: We are out of water. The only question is when!
//     Here is a list of all dwellers with their respective age int[] ageOfDweller.
//     In our tank currently are int water liters of water.
//     I want to know from you: How long will rich our supplies.
//
//     Remember!
//     Each dweller has a different water consumption.
//     A dweller under 18 consumes 1 liter per day, everyone older than 50 needs 1.5 liters and the rest needs 2 liters per day.
//     Each dweller must get its prescribed ration of water, every day!
//     If not satisfied all dweller, then our days are numbered.
//
//     Good luck! I'll bet on you!
//
//
// Note from Vault Technicians:
//     Your program returns a positive integer. The residual water is not calculated.
//     return -1; - If no dweller living inside of the Vault.

// SOLUTION:

function thirstyIn(water, ageOfDwellerArray) {
    if (ageOfDwellerArray.length <=0) return -1

    const waterDay = ageOfDwellerArray.map((age,index) =>{
        if(age < 18)  return 1
        if(age >= 18 && age <= 50) return 2
        if(age > 50) return 1.5
    })
    return Math.floor(water/waterDay.reduce((acc, el) =>acc+el,0))

}