Solve EverybodyCodes Story 1 Quest 1

Author: IsaacG

everybody_codes/story01/quest_01.py

@@ -0,0 +1,102 @@
+"""Everyone Codes Day N."""
+
+import re
+
+
+def eni(n: int, exp: int, mod: int, part: int) -> int:
+    """Return an ENI result."""
+    if part != 3:
+        remainders = []
+        if part == 1:
+            # Part 1: brute force each remainder.
+            score = 1
+            steps = exp
+        else:
+            # Part 2: higher values; skip to the end using pow() and compute 5 remainders.
+            score = pow(n, exp - 5, mod)
+            steps = 5
+
+        for step in range(steps):
+            score = score * n % mod
+            remainders.append(score)
+        return int("".join(str(i) for i in reversed(remainders)))
+
+    # Part 3: solve for each remainder with cycle finding.
+    seen = set()
+    scores = []
+    score = 1
+    for step in range(exp):
+        score = score * n % mod
+
+        # Stop on cycle detection.
+        if score in seen:
+            break
+
+        scores.append(score)
+        seen.add(score)
+
+    # Find how many steps since the score was last seen, ie cycle length.
+    prior_step = scores.index(score)
+    stride = step - prior_step
+    # How many times does the cycle repeat and how many steps after the last cycle?
+    div, rmod = divmod(exp - step, stride)
+    modsum = lambda x: sum(i % mod for i in x)
+    # Score: (steps prior to cycling) + (cycle scores repeated div times) + (steps after the last cycle).
+    return modsum(scores) + div * modsum(scores[prior_step:]) + modsum(scores[prior_step:prior_step + rmod])
+
+
+def verify_eni(a: int, b: int, c: int, x: int, y: int, z: int, m: int, part: int) -> int:
+    """Return the sum of three ENIs."""
+    return eni(a, x, m, part) + eni(b, y, m, part) + eni(c, z, m, part) 
+
+
+def solve(part: int, data: str) -> int:
+    """Solve the line which yields the highest ENI sum."""
+    return max(
+        verify_eni(*[int(i) for i in re.findall(r"[0-9]+", line)], part=part)
+        for line in data.splitlines()
+    )
+
+
+TEST_DATA = [
+    """\
+A=4 B=4 C=6 X=3 Y=4 Z=5 M=11
+A=8 B=4 C=7 X=8 Y=4 Z=6 M=12
+A=2 B=8 C=6 X=2 Y=4 Z=5 M=13
+A=5 B=9 C=6 X=8 Y=6 Z=8 M=14
+A=5 B=9 C=7 X=6 Y=6 Z=8 M=15
+A=8 B=8 C=8 X=6 Y=9 Z=6 M=16""",
+    """\
+A=4 B=4 C=6 X=3 Y=14 Z=15 M=11
+A=8 B=4 C=7 X=8 Y=14 Z=16 M=12
+A=2 B=8 C=6 X=2 Y=14 Z=15 M=13
+A=5 B=9 C=6 X=8 Y=16 Z=18 M=14
+A=5 B=9 C=7 X=6 Y=16 Z=18 M=15
+A=8 B=8 C=8 X=6 Y=19 Z=16 M=16""",
+    """\
+A=3657 B=3583 C=9716 X=903056852 Y=9283895500 Z=85920867478 M=188
+A=6061 B=4425 C=5082 X=731145782 Y=1550090416 Z=87586428967 M=107
+A=7818 B=5395 C=9975 X=122388873 Y=4093041057 Z=58606045432 M=102
+A=7681 B=9603 C=5681 X=716116871 Y=6421884967 Z=66298999264 M=196
+A=7334 B=9016 C=8524 X=297284338 Y=1565962337 Z=86750102612 M=145""",
+    """\
+A=4 B=4 C=6 X=3000 Y=14000 Z=15000 M=110
+A=8 B=4 C=7 X=8000 Y=14000 Z=16000 M=120
+A=2 B=8 C=6 X=2000 Y=14000 Z=15000 M=130
+A=5 B=9 C=6 X=8000 Y=16000 Z=18000 M=140
+A=5 B=9 C=7 X=6000 Y=16000 Z=18000 M=150
+A=8 B=8 C=8 X=6000 Y=19000 Z=16000 M=160""",
+    """\
+A=3657 B=3583 C=9716 X=903056852 Y=9283895500 Z=85920867478 M=188
+A=6061 B=4425 C=5082 X=731145782 Y=1550090416 Z=87586428967 M=107
+A=7818 B=5395 C=9975 X=122388873 Y=4093041057 Z=58606045432 M=102
+A=7681 B=9603 C=5681 X=716116871 Y=6421884967 Z=66298999264 M=196
+A=7334 B=9016 C=8524 X=297284338 Y=1565962337 Z=86750102612 M=145""",
+]
+TESTS = [
+    (1, TEST_DATA[0], 11611972920),
+    (2, TEST_DATA[1], 11051340),
+    (2, TEST_DATA[2], 1507702060886),
+    (3, TEST_DATA[3], 3279640),
+    (3, TEST_DATA[4], 7276515438396),
+]