Rearranged random move selection to avoid expensive division

2 files changed, 6 insertions, 11 deletions

diff --git a/src/engine/constants.rs b/src/engine/constants.rs
index 2e80988..458251f 100644
--- a/src/engine/constants.rs
+++ b/src/engine/constants.rs
@@ -28,7 +28,7 @@ pub const ENERGY_CONSTRUCTION_TIME: u8 = 1;
 
 pub const DECONSTRUCT_ENERGY: u16 = 5;
 
-pub const MAX_CONCURRENT_CONSTRUCTION: usize = 5; //2 teslas, and 3 of anything else
+pub const MAX_CONCURRENT_CONSTRUCTION: usize = 6; //2 teslas, and 3 of anything else, 1 extra because it's push here then update construction times
 
 
 #[cfg(not(feature = "reduced-time"))]
diff --git a/src/strategy/monte_carlo.rs b/src/strategy/monte_carlo.rs
index 25b5a66..0844402 100644
--- a/src/strategy/monte_carlo.rs
+++ b/src/strategy/monte_carlo.rs
@@ -126,21 +126,16 @@ fn random_opponent_move<R: Rng>(state: &BitwiseGameState, rng: &mut R) -> Comman
 
 // TODO: Given enough energy, most opponents won't do nothing
 fn random_move<R: Rng, F:Fn(usize)->Point>(all_buildings: &[BuildingType], rng: &mut R, free_positions_count: usize, get_point: F) -> Command {
-    let building_command_count = free_positions_count*all_buildings.len();
     let nothing_count = 1;
-
-    let number_of_commands = building_command_count + nothing_count;
+    let building_choice_index = rng.gen_range(0, nothing_count + all_buildings.len());
     
-    let choice_index = rng.gen_range(0, number_of_commands);
-
-    // TODO: Remove the divide here?
-
-    if choice_index == number_of_commands - 1 {
+    if building_choice_index == all_buildings.len() {
         Command::Nothing
     } else {
+        let position_choice = rng.gen_range(0, free_positions_count);
         Command::Build(
-            get_point(choice_index/all_buildings.len()),
-            all_buildings[choice_index%all_buildings.len()]
+            get_point(position_choice),
+            all_buildings[building_choice_index]
         )
     }
 }