growPlant.js

// Task
// Each day a plant is growing by upSpeed meters. Each night that plant's height decreases by downSpeed meters due to the lack of sun heat. Initially, plant is 0 meters tall. We plant the seed at the beginning of a day. We want to know when the height of the plant will reach a certain level.

// Example
// For upSpeed = 100, downSpeed = 10 and desiredHeight = 910, the output should be 10.

//  After day 1 --> 100
//  After night 1 --> 90
//  After day 2 --> 190
//  After night 2 --> 180
//  After day 3 --> 280
//  After night 3 --> 270
//  After day 4 --> 370
//  After night 4 --> 360
//  After day 5 --> 460
//  After night 5 --> 450
//  After day 6 --> 550
//  After night 6 --> 540
//  After day 7 --> 640
//  After night 7 --> 630
//  After day 8 --> 730
//  After night 8 --> 720
//  After day 9 --> 820
//  After night 9 --> 810
//  After day 10 --> 910 
// For upSpeed = 10, downSpeed = 9 and desiredHeight = 4, the output should be 1.

// Because the plant reach to the desired height at day 1(10 meters).

//  After day 1 --> 10
// Input/Output
// [input] integer upSpeed

// A positive integer representing the daily growth.

// Constraints: 5 ≤ upSpeed ≤ 100.

// [input] integer downSpeed

// A positive integer representing the nightly decline.

// Constraints: 2 ≤ downSpeed < upSpeed.

// [input] integer desiredHeight

// A positive integer representing the threshold.

// Constraints: 4 ≤ desiredHeight ≤ 1000.

// [output] an integer

// The number of days that it will take for the plant to reach/pass desiredHeight (including the last day in the total count).


function growingPlant(upSpeed, downSpeed, desiredHeight) {







    
    return desiredHeight <= upSpeed ? 1 : growingPlant(upSpeed, downSpeed, desiredHeight - (upSpeed-downSpeed)) + 1;







    
}


const growingPlant2=(u,d,h)=>Math.max(Math.ceil((h-u)/(u-d)),0)+1;




console.log(growingPlant(100,10,910));