day 11

11/a.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+
+SERIAL = 6878
+
+
+def getcelvalue(x, y):
+    """
+    Find the fuel cell's rack ID, which is its X coordinate plus 10.
+    Begin with a power level of the rack ID times the Y coordinate.
+    Increase the power level by the value of the grid serial number (your puzzle input).
+    Set the power level to itself multiplied by the rack ID.
+    Keep only the hundreds digit of the power level (so 12345 becomes 3; numbers with no hundreds digit become 0).
+    Subtract 5 from the power level.
+    """
+    rackid = x + 10
+    pwr = rackid * y
+    pwr += SERIAL
+    pwr *= rackid
+    pwr = int(pwr / 100) % 10
+    return pwr - 5
+
+
+def getregionvalue(x, y, size):
+    total = 0
+    for xi in range(x, x + size):
+        for yi in range(y, y + size):
+            total += getcelvalue(xi, yi)
+    return total
+
+
+def main():
+    bestcoords = None
+    bestvalue = 0
+    for x in range(1, 299):
+        for y in range(1, 299):
+            value = getregionvalue(x, y)
+            if value > bestvalue:
+                bestcoords = (x, y, )
+                bestvalue = value
+
+    print(bestcoords, bestvalue)
+
+
+if __name__ == '__main__':
+    main()

11/b.py

@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+
+
+SERIAL = 6878
+
+
+def getcelvalue(x, y):
+    """
+    Find the fuel cell's rack ID, which is its X coordinate plus 10.
+    Begin with a power level of the rack ID times the Y coordinate.
+    Increase the power level by the value of the grid serial number (your puzzle input).
+    Set the power level to itself multiplied by the rack ID.
+    Keep only the hundreds digit of the power level (so 12345 becomes 3; numbers with no hundreds digit become 0).
+    Subtract 5 from the power level.
+    """
+    rackid = x + 10
+    pwr = rackid * y
+    pwr += SERIAL
+    pwr *= rackid
+    pwr = int(pwr / 100) % 10
+    return pwr - 5
+
+
+def getregionbestsizevalue(x, y, sizemax):
+    """
+    Calculate each square size in passes as illustrated below
+    1 2 3 4
+    2 2 3 4
+    3 3 3 4
+    4 4 4 4
+    """
+    # size with the highest total
+    bestsize = None
+    # score of the best size
+    bestsizevalue = -999999
+    # maximum square we can fit
+    size = min(sizemax + 1 - x, sizemax + 1 - y)
+    # running total for this coordinate
+    total = 0
+    for sz in range(0, size):
+        # the column/row we're currently iterating
+        xcol = x + sz
+        yrow = y + sz
+        # iteration counters
+        yit = yrow - 1
+        xit = xcol
+        while yit >= y:
+            total += getcelvalue(xcol, yit)
+            yit -= 1
+        while xit >= x:
+            total += getcelvalue(xit, yrow)
+            xit -= 1
+
+        if total > bestsizevalue:
+            bestsizevalue = total
+            bestsize = sz
+
+    return (x, y, bestsize + 1, bestsizevalue)
+
+
+from concurrent.futures import ProcessPoolExecutor, as_completed
+from multiprocessing import cpu_count
+
+
+def main():
+    bestcoords = None
+    bestvalue = 0
+    compl = 0
+    todo = 300 * 300
+
+    with ProcessPoolExecutor(max_workers=cpu_count()) as pool:
+        futures = []
+        for x in range(1, 300):
+            for y in range(1, 300):
+                futures.append(pool.submit(getregionbestsizevalue, x, y, 300, ))
+
+        for f in as_completed(futures):
+            rx, ry, size, value = f.result()
+            if value > bestvalue:
+                bestvalue = value
+                bestcoords = (rx, ry, size)
+                print("new best:", bestcoords, "@", bestvalue)
+            compl += 1
+            if compl % 100 == 0:
+                print(compl, "({}%)".format(int(compl / todo * 100)))
+
+    print("Value:", bestvalue)
+    print("Solution:", ",".join([str(i) for i in bestcoords]))
+
+
+if __name__ == '__main__':
+    main()