Smarter smart dealer!

simulator/src/smart_dealer.rs

@@ -10,108 +10,167 @@ impl Deal {
     pub fn deal(setup: &Setup, rng: &mut impl Rng) -> Deal {
         loop {
             if let Some(d) = Self::deal1(setup, rng) {
-                return d
+                return d;
             }
         }
     }
+
     fn deal1(setup: &Setup, rng: &mut impl Rng) -> Option<Deal> {
-        // don't use the middle slot
-        let n_slots = (setup.ruleset.n_slots - 1) as usize;
-        let aux_slot = n_slots;
         let n_usable_cards = setup.ruleset.usable_n_cards();
-        let tower_height = n_usable_cards as usize / n_slots;
 
-        let mut slots: Vec<Vec<Card>> = vec![vec![]; n_slots+1];
+        // there are n - 1 final slots, because we don't use the middle one
+        let n_final_slots = (setup.ruleset.n_slots - 1) as usize;
 
-        let split_point = 
+        // we have an extra slot! it's the top slot, which blocks the wells
-            if setup.ruleset.n_arcana == 0 { 0 } 
+        let n_usable_slots = n_final_slots + 1;
-            else { rng.gen_range(0..setup.ruleset.n_arcana) };
 
+        let mut slots: Vec<Vec<Card>> = vec![vec![]; n_usable_slots];
+        let mut max_height: Vec<usize> = vec![0; n_usable_slots];
+        let tower_height = n_usable_cards as usize / n_final_slots;
+
+        for i in 1..=n_final_slots {
+            max_height[i] = tower_height;
+        }
+        max_height[0] = 1;
+
+        let mut wells = Self::generate_wells(setup, rng);
+        let mut pops = Self::plan_pops(&wells, rng);
+
+        while let Some(w) = pops.pop() {
+            let is_arcana = w >= setup.ruleset.n_suits as usize;
+
+            let mut exclude = None;
+            if !is_arcana {
+                // we can't put a card in the well if it's blocked, so make sure it's unblocked
+                if let Some(c) = slots[0].pop() {
+                    Self::find_home(setup, rng, 1.0, c, None, Some(0), &mut slots, &max_height);
+                }
+
+                exclude = Some(0);  // don't place the new card in the auxiliary slot
+            }
+
+            let card = wells[w].pop().expect("card must be present");
+
+            Self::find_home(setup, rng, 1.0, card, None, exclude, &mut slots, &max_height);
+
+            // do some moves from acceptors to random slots
+            const MAX_I: i32 = 48;
+            for i in 0..MAX_I+1 {
+                let src = rng.gen_range(0..slots.len());
+                if let Some(accepted_card) = Self::pop_accepted_card(setup, src, &mut slots) {
+                    Self::find_home(setup, rng, ((MAX_I - i) as f64)/(MAX_I as f64), accepted_card, Some(src), None, &mut slots, &max_height);
+                }
+            }
+        }
+
+        // are any stacks too tall? fix them
+        max_height[0] = 0;  // auxiliary slot must be empty
+        for i in 0..slots.len() {
+            while slots[i].len() > max_height[i] {
+                let card = slots[i].pop().expect("must be a card");
+                Self::find_home(setup, rng, 0.0, card, None, None, &mut slots, &max_height);
+            }
+        }
+
+        slots.remove(0);  // get rid of the auxiliary slot
+        if !Self::fix_instantly_accepted(setup, &mut slots) {
+            return None;
+        }
+
+        for s in slots.iter() {
+            assert_eq!(tower_height, s.len());
+        }
+
+        return Some(Deal { slots } )
+    }
+
+    fn generate_wells(setup: &Setup, rng: &mut impl Rng) -> Vec<Vec<Card>> {
+        let split_point =
+            if setup.ruleset.n_arcana == 0 { 0 }
+            else { rng.gen_range(0..=setup.ruleset.n_arcana) };
+        
         let n_wells = setup.ruleset.n_suits + 2;
 
-        let mut virtual_wells: Vec<Vec<Card>> = vec![vec![]; n_wells as usize + 2];
+        let mut wells: Vec<Vec<Card>> = vec![vec![]; n_wells as usize + 2];
 
-        // rely on the order of the deck
+        // fill the wells in suit order, relying on the order of the deck object
-        for r in 1..setup.ruleset.n_cards_per_suit {  // skip aces
+        for r in 1..setup.ruleset.n_cards_per_suit {
             for s in 0..setup.ruleset.n_suits {
-                virtual_wells[s as usize].push(Card(setup.ruleset.n_cards_per_suit * s + r));
+                wells[s as usize].push(Card(setup.ruleset.n_cards_per_suit * s + r))
             }
-        } 
+        }
 
+        // now fill the wells for arcana
         let first_arcana = setup.ruleset.n_suits * setup.ruleset.n_cards_per_suit;
+        let arcana0 = setup.ruleset.n_suits as usize;
+        let arcana1 = arcana0 + 1;
         for r in 0..split_point {
-            virtual_wells[setup.ruleset.n_suits as usize].push(Card(r+first_arcana))
+            wells[arcana0].push(Card(first_arcana + r));
         }
         for r in (split_point..setup.ruleset.n_arcana).rev() {
-            virtual_wells[setup.ruleset.n_suits as usize + 1].push(Card(r+first_arcana))
+            wells[arcana1].push(Card(first_arcana + r));
         }
 
+        wells
+    }
+
+    fn plan_pops(wells: &[Vec<Card>], rng: &mut impl Rng) -> Vec<usize> {
         let mut pops = vec![];
-        for (well, contents) in virtual_wells.iter().enumerate() {
+        for (well, contents) in wells.iter().enumerate() {
             for _ in 0..contents.len() {
                 pops.push(well);
             }
         }
         pops.shuffle(rng);
+        pops
+    }
 
-        fn find_home(card: Card, exclude: Option<usize>, setup: &Setup, slots: &mut [Vec<Card>], aux_slot: usize, tower_height: usize, rng: &mut impl Rng) {
+    fn peek2(stack: &Vec<Card>) -> (Option<Card>, Option<Card>) {
-            let mut acceptors = vec![];
+        let mut iter = stack.iter().rev();
-            let mut not_full = vec![];
+        let top = iter.next().cloned();
-            for s in 0..slots.len() {
+        let second_to_top = iter.next().cloned();
-                let not_too_tall = slots[s].len() < if s == aux_slot { 1 } else { tower_height };
+        return (second_to_top, top);
-                if Some(s) != exclude {
+    }
-                    if not_too_tall && accepts(setup, slots[s].last().cloned(), card) {
-                        acceptors.push(s)
-                    }
-                    if not_too_tall {
-                        not_full.push(s);
-                    }
-                }
-            }
 
-            acceptors.shuffle(rng);
+    fn find_home(setup: &Setup, rng: &mut impl Rng, acceptor_odds: f64, card: Card, source: Option<usize>, exclude: Option<usize>, slots: &mut [Vec<Card>], max_height: &[usize]) {
-            not_full.shuffle(rng);
+        // if a card is sitting on an acceptor, it could have been moved there
-            if rng.gen_bool(0.5) && acceptors.len() > 0 {
+        // from somewhere else
-                let a = acceptors.first().unwrap();
+        let mut acceptors = vec![];
-                slots[*a].push(card);
+
-            } else if let Some(a) = not_full.first() {
+        // if a card is sitting on a start point, it could not have been moved
-                slots[*a].push(card);
+        // there from somewhere else
-            } else if let Some(e) = exclude {
+        let mut start_points = vec![];
-                slots[e].push(card)
+
+        for s in 0..slots.len() {
+            if Some(s) == exclude {
+                // don't place it here, ever
             } else {
-                panic!("should not ever happen")
+                if accepts(setup, slots[s].last().cloned(), card) {
-            }
+                    acceptors.push(s);
-        }
+                }
 
-        while let Some(w) = pops.pop() {
+                if slots[s].len() < max_height[s] {
-            let card = virtual_wells[w].pop().expect("card must be present");
+                    start_points.push(s);
-            find_home(card, None, setup, &mut slots, aux_slot, tower_height, rng);
-
-            // move any card that is on an acceptor to a random slot
-            for _ in 0..15 {
-                let mut sources: Vec<usize> = (0..slots.len()).collect();
-                sources.shuffle(rng);
-                for src in sources {
-                    let mut iter = slots[src].iter().rev();
-                    let top = iter.next().cloned();
-                    let second_to_top = iter.next().cloned();
-
-                    if let Some(t) = top {
-                        if accepts(&setup, second_to_top, t) {
-                            slots[src].pop();
-                            find_home(t, Some(src), setup, &mut slots, aux_slot, tower_height, rng);
-                        }
-                    }
                 }
             }
         }
 
-        if let Some(top) = slots[n_slots].pop() {
+        let mut acceptor = acceptors.choose(rng).cloned();
-            assert!(slots[n_slots].len() == 0);
+        let start_point = start_points.choose(rng).cloned();
-            find_home(top, Some(n_slots), setup, &mut slots, aux_slot, tower_height, rng);
+        if !rng.gen_bool(acceptor_odds) {
-            assert!(slots[n_slots].len() == 0);
+            // don't use an acceptor even though we could
+            acceptor = None;
         }
 
+        if let Some(a) = acceptor.or(start_point).or(source) {
+            slots[a].push(card);
+        } else {
+            panic!("should not ever happen");
+        }
+    }
+
+    fn fix_instantly_accepted(setup: &Setup, slots: &mut [Vec<Card>]) -> bool {
+        let first_arcana = setup.ruleset.n_suits * setup.ruleset.n_cards_per_suit;
         let mut instantly_accepted = vec![];
         for &a in &setup.deck.aces {
             instantly_accepted.push(Card(a.0 + 1))  // twos
@@ -119,38 +178,39 @@ impl Deal {
         instantly_accepted.push(Card(first_arcana));
         instantly_accepted.push(Card(first_arcana + setup.ruleset.n_arcana - 1));
 
-        for s in 0..n_slots {
+        for s in 0..slots.len() {
-            let mut iter = slots[s].iter().rev();
+            let (second_to_last, last) = Self::peek2(&slots[s]);
-            let last = iter.next().cloned();
-            let second_to_last = iter.next().cloned();
 
             if let Some(last) = last {
                 if instantly_accepted.contains(&last) {
                     if let Some(c) = second_to_last {
                         if instantly_accepted.contains(&c) {
-                            return None
+                            return false
                         }
 
                         let n = slots[s].len();
                         (slots[s][n-2],slots[s][n-1]) = (last, c);
                     }
                     else {
-                        return None;
+                        return false;  // confusing nonsense situation
                     }
                 }
             }
         }
-
+        return true;
-
-        for s in 0..n_slots {
-            assert!(slots[s].len() == tower_height)
-        }
-
-        slots.pop();  // get rid of aux slot
-
-        return Some(Deal { slots });
     }
 
+    fn pop_accepted_card(setup: &Setup, src: usize, slots: &mut [Vec<Card>]) -> Option<Card> {
+        let (card0, card1) = Self::peek2(&slots[src]);
+
+        if let Some(c1) = card1 {
+            if accepts(&setup, card0, c1) {
+                slots[src].pop().expect("we just peeked at this");
+                return Some(c1);
+            }
+        }
+        None
+    }
 }
 
 fn accepts(setup: &Setup, prev: Option<Card>, next: Card) -> bool {