2410 - Area of Squares

[ymondelo20]

http://coj.uci.cu/24h/problem.xhtml?abb=2410

[EduardoQuintana]

Basic geometry knowledge is necessary to solve this.
The length of the edge of the biggest square is given (A1). The length of the next square's edge (A2) can be easily found using Pitágora's relation:
A2=sqrt( (A1/2)^2 + (A1/2)^2 )=A1/sqrt(2).
Repeating the same reasoning for further minor squares inscribed, it is found that the length of the i_th square's edge (Ai) can be computed as:
Ai=A1/sqrt(2^(i-1)).
The area of the ith square is clearly the length of side squared:
Area_i = Ai^2 = A1^2/2^(i-1)

Pretty simple.

For avoiding machine precision errors, you should use double instead of float variables.
Further machine precision errors can be eluded by adding a small amount to your result, example:

Code: Select all

const double eps=1e-6;

This will deal with tricky cases such as:
1/8=0.125000, rounded to %.2lf -> 0.13
for which some compilers would return instead 1/8=0.124999, rounded to %.2lf -> 0.12 == Wrong Answer

[ymondelo20]

A easy problem, with one tricky detail.
Good explanation.
Regards

[HaZard]

muy buena explicacion, gracias por eso

[DiMas]

Hola a todos, comprendo perfectamente la formula dada en el post que explica la solucion, de hecho, habia enviado el resultado antes de consultar aqui, pero, dado el bajo porcentaje de aceptados decidi mirar y me di cuenta de que llego al mismo resultado y obtengo wA, podrian por favor decirme que pasa.
Muchas Gracias.Atentamente
Dimas

[HaZard]

Hola a todos, comprendo perfectamente la formula dada en el post que explica la solucion, de hecho, habia enviado el resultado antes de consultar aqui, pero, dado el bajo porcentaje de aceptados decidi mirar y me di cuenta de que llego al mismo resultado y obtengo wA, podrian por favor decirme que pasa.
Muchas Gracias.Atentamente
Dimas

En el post de quintana viene bien explicado, leelo cuidadosamente, Saludos

For avoiding machine precision errors, you should use double instead of float variables.
Further machine precision errors can be eluded by adding a small amount to your result, example:

Code: Select all

const double eps=1e-6;

This will deal with tricky cases such as:
1/8=0.125000, rounded to %.2lf -> 0.13
for which some compilers would return instead 1/8=0.124999, rounded to %.2lf -> 0.12 == Wrong Answer