JavaScript Fun Question: Bouncy Ball

A naughty kid is playing with a bouncy ball on a tall building that is h meters high. h is measured in meters.

Then, he threw the bouncy ball, and the ball quickly rebounded to the height of the original bounce, such as 2/3 two-thirds.

His mother was currently at a height of window, looking out the window. window should be smaller than h, that is to say, His mother was definitely beneath him.

Excuse me, how many times can this mother see the ball in front of the window? Includes both decline and rebound.

Note:

Only if the height of the ball’s rebound is absolutely greater than window, this mother can see it.

Example:

h = 3, bounce = 0.66, window = 1.5, the result is 3

h = 3 , bounce = 1, window = 1.5, the result is -1

If there is an abnormal value here, -1 will be returned.

What kind of situation is considered an outlier?

1.bounceBounce rate or >=1, such a situation is obviously impossible

2. The height of the naughty child is lower than his mother, so it is meaningless. Return directly to -1

Okay, let’s take a look at the idea:

1. Under normal circumstances, the mother will see the bouncy ball at least once when it falls for the first time.

2. If the height of the rebound is greater than window, then 2 times will be added each time it goes up and down.

Well, first eliminate the outliers, and then write according to the above ideas:

function bouncingBall(h,  bounce,  window) {
    var total = -1;
    if(bounce <= 0 || bounce >= 1){
        return total;
    }
    if(h > window){
        total = 1;
        var current = h * bounce;
        while(current > window){
            total += 2;
            current = current * bounce;
        }
    }
    return total;
}

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