Solution to day 22.

day-22/solution.py

@@ -0,0 +1,107 @@
+from __future__ import print_function, division
+from queue import PriorityQueue
+
+def applyEffects(current):
+    if current['recharge'] > 0:
+        current['mana'] += 101
+        current['recharge'] -= 1
+
+    if current['shield'] > 0:
+        current['shield'] -= 1
+
+    if current['poison'] > 0:
+        current['poison'] -= 1
+        current['bossHP'] -= 3
+
+
+def dijkstraMagic(initialState, hard):
+    todo = PriorityQueue()
+    todo.put((0, 0, initialState.copy()))
+
+    visited = {tuple(initialState.values()): 0}
+    iteration = 0
+
+    while not todo.empty():
+        iteration += 1
+        top = todo.get()
+        current = top[2].copy()
+        manaSpent = top[0]
+
+        if hard:
+            # Hard mode
+            current['hp'] -= 1
+
+        if current['hp'] <= 0:
+            # Already dead
+            continue
+
+        applyEffects(current)
+
+        if current['bossHP'] <= 0:
+            # We won!
+            return manaSpent
+
+        # Try every available spell
+        for spell in spells:
+            if current['mana'] < spell[1]:
+                # Not enough mana to cast
+                continue
+
+            if spell[4] is not None and current[spell[4]] > 0:
+                # Effect still active
+                continue
+
+            newState = current.copy()
+            newState['bossHP'] -= spell[2]
+            newState['mana'] -= spell[1]
+            newState['hp'] += spell[3]
+            if spell[4] is not None:
+                newState[spell[4]] = spell[5]
+
+            newMana = manaSpent + spell[1]
+
+            # Start Boss turn
+            applyEffects(newState)
+
+            if newState['bossHP'] > 0:
+                # Alive to attack?
+                if newState['shield'] > 0:
+                    damage = 2
+                else:
+                    damage = 9
+
+                newState['hp'] -= damage
+            else:
+                # Died during effects
+                return newMana
+
+            if newState['hp'] > 0:
+                # New state
+                key = tuple(newState.values())
+                if key not in visited or visited[key] > newMana:
+                    # Insert the route in to the visited and queue
+                    visited[key] = newMana
+                    todo.put((newMana, iteration, newState))
+
+    return None
+
+spells = [
+        # Name, Mana, Damage, Heal, Effect, Turns
+        ("Magic Missile", 53, 4, 0, None, 0),
+        ("Drain", 73, 2, 2, None, 0),
+        ("Shield", 113, 0, 0, "shield", 6),
+        ("Poison", 173, 0, 0, "poison", 6),
+        ("Recharge", 229, 0, 0, "recharge", 5),
+        ]
+
+status = {
+        "bossHP": 51,
+        "hp": 50,
+        "mana": 500,
+        "shield": 0,
+        "poison": 0,
+        "recharge": 0
+        }
+
+print(dijkstraMagic(status, False))
+print(dijkstraMagic(status, True))