Added special case for a point that can be known to be a hit while seeking

Shooting here first will eliminate a ship immediately that might
otherwise be dumbly left until the end of the game, where a spot that
can only be one ship shows up on the overall probability density
graph.

It also does meaningful shots while recharging specials shots to speed
up the random part of searching.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/knowledge.rs b/src/knowledge.rs
index 1923f41..4a66e8b 100644
--- a/src/knowledge.rs
+++ b/src/knowledge.rs
@@ -170,6 +170,11 @@ impl Knowledge {
         let possible_placements = self.opponent_map.possible_placements();
         // let lattice = self.lattice_size(); //TODO use the lattice still?
 
+        let guaranteed_hits = self.get_points_that_touch_all_possibilities_on_unsunk_ship();
+        if !guaranteed_hits.is_empty() {
+            return (Weapon::SingleShot, guaranteed_hits);
+        }
+
         let mut best_shots: HashMap<Weapon, (Vec<Point>, usize)> = HashMap::new();
         
         for &weapon in self.available_weapons.iter() {
@@ -234,6 +239,16 @@ impl Knowledge {
         (best.0.clone(), (best.1).0)
     }
 
+    fn get_points_that_touch_all_possibilities_on_unsunk_ship(&self) -> Vec<Point> {
+        self.opponent_map.flat_cell_position_list().iter().cloned().filter(|&point| {
+            self.opponent_map.ships.values()
+                .any(|ref ship| !ship.destroyed &&
+                     ship.possible_placements.iter().all(|placement| {
+                         placement.touches_point(point)
+                     }))
+        }).collect()
+    }
+
     fn lattice_size(&self) -> u16 {
         let any_long_ships = self.opponent_map.ships.iter()
             .any(|(ship, knowledge)| ship.length() >= 4 && !knowledge.destroyed);