1 files changed, 131 insertions, 0 deletions
diff --git a/bots/peter_smart.py b/bots/peter_smart.py
new file mode 100755
index 0000000..b099cdd
--- /dev/null
+++ b/bots/peter_smart.py
@@ -0,0 +1,131 @@
+#!/usr/bin/env python
+"""New and improved bot, OPTIMISED!!"""
+
+import random
+import sys
+
+DEBUG = False
+
+# Show tracebacks, then pause for debugging.
+if DEBUG:
+    sys_excepthook = sys.excepthook
+    def excepthook(*args, **kwargs):
+        sys_excepthook(*args, **kwargs)
+        import time
+        time.sleep(10)
+    sys.excepthook = excepthook
+
+EMPTY_TILE = '.'
+APPLE_TILE = '*'
+
+WIDTH, HEIGHT, SNAKE_BODY = raw_input().split()
+WIDTH = int(WIDTH)
+HEIGHT = int(HEIGHT)
+
+SNAKE_BODY = SNAKE_BODY.lower()
+SNAKE_HEAD = SNAKE_BODY.upper()
+
+HEADX = None
+HEADY = None
+
+SNAKE_LENGTH = 0
+
+def get_cell(board, x, y):
+    if x < 0 or x >= WIDTH or y < 0 or y >= HEIGHT:
+        raise KeyError, 'out of range.'
+    return board[y][x]
+
+BOARD = []
+for y in xrange(HEIGHT):
+    row = raw_input()
+    for x, char in enumerate(row):
+        if char == SNAKE_HEAD:
+            HEADX = x
+            HEADY = y
+        elif char == SNAKE_BODY:
+            SNAKE_LENGTH += 1
+    BOARD.append(row)
+
+MOVES = (
+    (-1, 0, 'l'),
+    (1, 0, 'r'),
+    (0, -1, 'u'),
+    (0, 1, 'd')
+)
+
+def get_score(x, y, n, done=None):
+    if done is None:
+        done = set()
+
+    done.add((x, y))
+
+    score = 0
+    explore = False
+
+    # See if the cell exists.
+    try:
+        square = get_cell(BOARD, x, y)
+    except KeyError:
+        return 0
+
+    # Give some extra points for getting an apple.
+    if square == APPLE_TILE:
+        explore = True
+        score += 50
+
+    # Yay - it's empty!
+    elif square == EMPTY_TILE:
+        explore = True
+        score += 10
+
+    elif square.islower():
+        score -= 1
+
+    if explore and n > 0:
+        # Explore n-1 cells further.
+        for dx, dy, move in MOVES:
+            nx = x + dx
+            ny = y + dy
+
+            if (nx, ny) in done:
+                continue
+
+            subscore = get_score(nx, ny, n - 1, done)
+            score += subscore / 10
+
+    return score * n
+
+max_score = None
+max_moves = []
+
+for dx, dy, move in MOVES:
+    score = 0
+
+    x = HEADX + dx
+    y = HEADY + dy
+
+    n = (SNAKE_LENGTH + 4) / 2
+    score = get_score(x, y, n)
+
+#    print 'Score for', move, '=', score
+
+    # Suicide protection squad!
+    try:
+        square = get_cell(BOARD, x, y)
+    except KeyError:
+        continue
+    else:
+        if square not in (APPLE_TILE, EMPTY_TILE):
+            continue
+
+    if score == max_score:
+        max_moves.append(move)
+    elif max_score is None or score > max_score:
+        max_score = score
+        max_moves = [move]
+
+if max_moves:
+    print random.choice(max_moves)
+else:
+    raise Exception, "No suitable moves found!"
+