i have a problem, i need some explanation for how to fix it, can i get some help please ?

full problem:

collision problem:

there are n particles numbered from 0 to n-1 lined up from smallest to largest ID along the x-axis.

the particles are all released simultaneously. once released, each particle travels indefinitely in a straight line along the positive x-axis at a speed.

when two particles collide, the faster particle moves through the slower particles and they both continue moving without changing speed or direction.

write a function that return the number of collision occurring with particle pos.

collision has the following parameters:

speed[speed[0] … speed[n-1]]: an array of speed[i] indication speed of particle i.

pos: index of the particle for which to count collisions.

constraints

- 1 <= n <= 100000
- 1 <= speed[i] <= 1000000000
- 0 <= pos< n

input:

8

6

1

6

3

4

6

8

2

output:

2

explanation:

the particle at pos = 2 will collide with particle 0 and 1 as they pass it from behind.