From 6917ffc2a3c571782c8a3b473e02d5ccf39cd7c0 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin@worthe-it.co.za>
Date: Sun, 26 May 2019 18:24:16 +0200
Subject: A bit faster through caching set of occupied spots

---
 src/game.rs | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/game.rs b/src/game.rs
index 982c276..18731a2 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -12,6 +12,7 @@ mod map;
 use map::*;
 
 use arrayvec::ArrayVec;
+use fnv::FnvHashSet;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub struct GameBoard {
@@ -20,6 +21,7 @@ pub struct GameBoard {
     pub players: [Player; 2],
     pub powerups: ArrayVec<[Powerup; 2]>,
     pub map: Map,
+    pub occupied_cells: FnvHashSet<Point2d<i8>>,
     pub outcome: SimulationOutcome
 }
 
@@ -65,11 +67,17 @@ impl GameBoard {
                 map.set(Point2d::new(cell.x, cell.y))
             }
         }
+
+        let players = [player, opponent];
+        let occupied_cells = players.iter()
+                .flat_map(|p| p.worms.iter())
+                .map(|w| w.position)
+                .collect();
             
         GameBoard {
             round: json.current_round,
             max_rounds: json.max_rounds,
-            players: [player, opponent],
+            players,
             powerups: json.map.iter().flatten().filter_map(|c| {
                 c.powerup.as_ref().map(|p| Powerup {
                     position: Point2d::new(c.x, c.y),
@@ -77,6 +85,7 @@ impl GameBoard {
                 })
             }).collect(),
             map,
+            occupied_cells,
             outcome: SimulationOutcome::Continue
         }
     }
@@ -119,6 +128,11 @@ impl GameBoard {
 
         self.round += 1;
         debug_assert_eq!(json.current_round, self.round);
+
+        self.occupied_cells = self.players.iter()
+            .flat_map(|p| p.worms.iter())
+            .map(|w| w.position)
+            .collect();
     }
 
     pub fn simulate(&mut self, moves: [Command; 2]) {
@@ -173,6 +187,9 @@ impl GameBoard {
                                 "Tried to move too far away, ({}, {})", p.x, p.y
                             );
 
+                            self.occupied_cells.remove(&worm.position);
+                            self.occupied_cells.insert(p);
+
                             worm.position = p;
                             
                             self.powerups.retain(|power| {
@@ -239,6 +256,7 @@ impl GameBoard {
                                     if target_worm.health <= 0 {
                                         // TODO: This will probably be changed soon https://github.com/EntelectChallenge/2019-Worms/issues/42
                                         self.players[player_index].moves_score += 40;
+                                        self.occupied_cells.remove(&target_worm.position);
                                     } else {
                                         self.players[player_index].moves_score -= 20;
                                     }
@@ -252,6 +270,7 @@ impl GameBoard {
                                     target_worm.health -= weapon_damage;
                                     if target_worm.health <= 0 {
                                         self.players[player_index].moves_score += 40;
+                                        self.occupied_cells.remove(&target_worm.position);
                                     } else {
                                         self.players[player_index].moves_score += 20;
                                     }
@@ -274,19 +293,13 @@ impl GameBoard {
         (player_index + 1)%2
     }
 
-
     pub fn valid_move_commands(&self, player_index: usize) -> ArrayVec<[Command;8]> {
         if let Some(worm) = self.players[player_index].active_worm() {
-            let taken_positions = self.players.iter()
-                .flat_map(|p| p.worms.iter())
-                .map(|w| w.position)
-                .collect::<ArrayVec<[Point2d<i8>; 6]>>();
-            
             Direction::all()
                 .iter()
                 .map(Direction::as_vec)
                 .map(|d| worm.position + d)
-                .filter(|p| !taken_positions.contains(p))
+                .filter(|p| !self.occupied_cells.contains(p))
                 .filter_map(|p| match self.map.at(p) {
                     Some(false) => Some(Command::Move(p)),
                     Some(true) => Some(Command::Dig(p)),
-- 
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