diff --git a/lib/std/math.zig b/lib/std/math.zig index 262d741e43..78acd4b90c 100644 --- a/lib/std/math.zig +++ b/lib/std/math.zig @@ -235,6 +235,7 @@ pub const sinh = @import("math/sinh.zig").sinh; pub const cosh = @import("math/cosh.zig").cosh; pub const tanh = @import("math/tanh.zig").tanh; pub const gcd = @import("math/gcd.zig").gcd; +pub const lcm = @import("math/lcm.zig").lcm; pub const gamma = @import("math/gamma.zig").gamma; pub const lgamma = @import("math/gamma.zig").lgamma; @@ -395,6 +396,7 @@ test { _ = cosh; _ = tanh; _ = gcd; + _ = lcm; _ = gamma; _ = lgamma; diff --git a/lib/std/math/lcm.zig b/lib/std/math/lcm.zig new file mode 100644 index 0000000000..8187102a6e --- /dev/null +++ b/lib/std/math/lcm.zig @@ -0,0 +1,29 @@ +//! Least common multiple (https://mathworld.wolfram.com/LeastCommonMultiple.html) +const std = @import("std"); + +/// Returns the least common multiple (LCM) of two integers (`a` and `b`). +/// For example, the LCM of `8` and `12` is `24`, that is, `lcm(8, 12) == 24`. +/// If any of the arguments is zero, then the returned value is 0. +pub fn lcm(a: anytype, b: anytype) @TypeOf(a, b) { + // Behavior from C++ and Python + // If an argument is zero, then the returned value is 0. + if (a == 0 or b == 0) return 0; + return @abs(b) * (@abs(a) / std.math.gcd(@abs(a), @abs(b))); +} + +test lcm { + const expectEqual = std.testing.expectEqual; + + try expectEqual(lcm(0, 0), 0); + try expectEqual(lcm(1, 0), 0); + try expectEqual(lcm(-1, 0), 0); + try expectEqual(lcm(0, 1), 0); + try expectEqual(lcm(0, -1), 0); + try expectEqual(lcm(7, 1), 7); + try expectEqual(lcm(7, -1), 7); + try expectEqual(lcm(8, 12), 24); + try expectEqual(lcm(-23, 15), 345); + try expectEqual(lcm(120, 84), 840); + try expectEqual(lcm(84, -120), 840); + try expectEqual(lcm(1216342683557601535506311712, 436522681849110124616458784), 16592536571065866494401400422922201534178938447014944); +}