Project Euler

Problem #212

An axis-aligned cuboid, specified by parameters { (x_(0),y_(0),z_(0)), (dx,dy,dz) }, consists of all points (X,Y,Z) such that x_(0) ≤ X ≤ x_(0)+dx, y_(0) ≤ Y ≤ y_(0)+dy and z_(0) ≤ Z ≤ z_(0)+dz. The volume of the cuboid is the product, dx × dy × dz. The combined volume of a collection of cuboids is the volume of their union and will be less than the sum of the individual volumes if any cuboids overlap.

Let C_(1),...,C_(50000) be a collection of 50000 axis-aligned cuboids such that C_(n) has parameters

x_(0) = S_(6n-5) modulo 10000
y_(0) = S_(6n-4) modulo 10000
z_(0) = S_(6n-3) modulo 10000
dx = 1 + (S_(6n-2) modulo 399)
dy = 1 + (S_(6n-1) modulo 399)
dz = 1 + (S_(6n) modulo 399)

where S_(1),...,S_(300000) come from the "Lagged Fibonacci Generator":

For 1 ≤ k ≤ 55, S_(k) = [100003 - 200003k + 300007k^(3)]   (modulo 1000000)
For 56 ≤ k, S_(k) = [S_(k-24) + S_(k-55)]   (modulo 1000000)

Thus, C_(1) has parameters {(7,53,183),(94,369,56)}, C_(2) has parameters {(2383,3563,5079),(42,212,344)}, and so on.

The combined volume of the first 100 cuboids, C_(1),...,C_(100), is 723581599.

What is the combined volume of all 50000 cuboids, C_(1),...,C_(50000) ?