diff --git a/2015/day22-input b/2015/day22-input
new file mode 100644
index 0000000..7f98dd7
--- /dev/null
+++ b/2015/day22-input
@@ -0,0 +1,2 @@
+Hit Points: 58
+Damage: 9
diff --git a/2015/day22.py b/2015/day22.py
new file mode 100644
index 0000000..2441242
--- /dev/null
+++ b/2015/day22.py
@@ -0,0 +1,139 @@
+with open('day22-input', 'r') as file:
+  data = [l.strip('\n') for l in file]
+boss_hp = int(data[0].split()[-1])
+boss_damage = int(data[1].split()[-1])
+player_hp = 50
+player_mp = 500
+
+from collections import namedtuple
+State = namedtuple('State', ['player_hp', 'player_mp', 'boss_hp', 'shield', 'poison', 'recharge', 'mp_spent'])
+
+initial_state = State(player_hp, player_mp, boss_hp, 0, 0, 0, 0)
+
+def magic_missile(state):
+  if state.player_mp < 53:
+    raise ValueError('Not enough mana')
+  return State(state.player_hp, state.player_mp-53, state.boss_hp-4,
+               state.shield, state.poison, state.recharge, state.mp_spent+53)
+
+def drain(state):
+  if state.player_mp < 73:
+    raise ValueError('Not enough mana')
+  return State(state.player_hp+2, state.player_mp-73, state.boss_hp-2,
+               state.shield, state.poison, state.recharge, state.mp_spent+73)
+
+def poison(state):
+  if state.player_mp < 173:
+    raise ValueError('Not enough mana')
+  if state.poison > 0:
+    raise ValueError('Already poisoned')
+  return State(state.player_hp, state.player_mp-173, state.boss_hp,
+               state.shield, state.poison+6, state.recharge, state.mp_spent+173)
+
+def shield(state):
+  if state.player_mp < 113:
+    raise ValueError('Not enough mana')
+  if state.shield > 0:
+    raise ValueError('Already shielded')
+  return State(state.player_hp, state.player_mp-113, state.boss_hp,
+               state.shield+6, state.poison, state.recharge, state.mp_spent+113)
+
+def recharge(state):
+  if state.player_mp < 229:
+    raise ValueError('Not enough mana')
+  if state.recharge > 0:
+    raise ValueError('Already recharging')
+  return State(state.player_hp, state.player_mp-229, state.boss_hp,
+               state.shield, state.poison, state.recharge+5, state.mp_spent+229)
+
+def turn_start(state, hardmode_player_turn=False):
+  s = state._asdict()
+  if hardmode_player_turn:
+    s['player_hp'] -= 1
+    if s['player_hp'] <= 0:
+      return State(**s)
+  if s['recharge'] > 0:
+    s['player_mp'] += 101
+    s['recharge'] -= 1
+  if s['poison'] > 0:
+    s['boss_hp'] -= 3
+    s['poison'] -= 1
+  if s['shield'] > 0:
+    s['shield'] -= 1
+  return State(**s)
+
+def boss_action(state):
+  damage = boss_damage
+  if state.shield > 0:
+    damage = max(damage-7, 1)
+  return State(state.player_hp-damage, state.player_mp, state.boss_hp,
+               state.shield, state.poison, state.recharge, state.mp_spent)
+
+spells = [magic_missile, drain, shield, poison, recharge]
+mana_reqs = [53, 73, 113, 173, 229]
+def execute_round(state, command, hardmode=False):
+  state = turn_start(state, hardmode)
+  if state.player_hp <= 0:
+    return state
+  state = spells[command](state)
+  state = turn_start(state)
+  if state.boss_hp > 0:
+    state = boss_action(state)
+  return state
+
+maximum_mana_usage = 100000  # Arbitrarily large
+winning_commands = []
+def tree_simulation(state, commands, hardmode=False):
+  global maximum_mana_usage, winning_commands
+
+  state = execute_round(state, commands[-1], hardmode)
+  if state.player_hp <= 0 or state.mp_spent > maximum_mana_usage:
+    return 100000
+  if state.boss_hp <= 0:
+    maximum_mana_usage = state.mp_spent
+    winning_commands = commands
+    return state.mp_spent
+
+  mp_spent = 100000
+  for cmd, mana in enumerate(mana_reqs):
+    if state.player_mp > mana:
+      try:
+        mp_spent = min(tree_simulation(state, commands+[cmd], hardmode), mp_spent)
+      except ValueError:
+        pass
+  return mp_spent
+
+mana = min([tree_simulation(initial_state, [c]) for c in range(len(spells))])
+print(mana)  # Part 1
+part1_commands = winning_commands
+
+maximum_mana_usage = 100000
+mana_hard = min([tree_simulation(initial_state, [c], hardmode=True) for c in range(len(spells))])
+print(mana_hard)  # Part 2
+part2_commands = winning_commands
+
+# Bonus: show the winning simulations
+spell_names = ['Magic Missile', 'Drain', 'Shield', 'Poison', 'Recharge']
+
+def perform_simulation(command_list, maximum_mana_usage=None, hardmode=False):
+  state = initial_state
+  for i, command in enumerate(command_list):
+    print(state)
+    print(f'Player casts {spell_names[command]}!')
+    try:
+      state = execute_round(state, command, hardmode)
+    except ValueError:
+      return f'Failed at round #{i+1}: Insufficient mana'
+    if maximum_mana_usage and state.mp_spent >= maximum_mana_usage:
+      return f'Failed at round #{i+1}: Exceeded mana budget'
+    if state.player_hp <= 0:
+      return f'Failed at round #{i+1}: Player died'
+    if state.boss_hp <= 0:
+      return f'Succeeded at round #{i+1}', state.mp_spent
+  return f'Ran out of commands but game is not over', state
+
+print('Ideal normal mode fight:')
+print(perform_simulation(part1_commands))
+print('')
+print('Ideal hard mode fight:')
+print(perform_simulation(part2_commands, hardmode=True))