Data commit

Task/Lychrel-numbers/Python/lychrel-numbers-1.py

@@ -0,0 +1,48 @@
+from __future__ import print_function
+
+def add_reverse(num, max_iter=1000):
+    i, nums = 0, {num}
+    while True:
+        i, num = i+1, num + reverse_int(num)
+        nums.add(num)
+        if reverse_int(num) == num or i >= max_iter:
+            break
+    return nums
+
+#@functools.lru_cache(maxsize=2**20)
+def reverse_int(num):
+    return int(str(num)[::-1])
+
+def split_roots_from_relateds(roots_and_relateds):
+    roots = roots_and_relateds[::]
+    i = 1
+    while i < len(roots):
+        this = roots[i]
+        if any(this.intersection(prev) for prev in roots[:i]):
+            del roots[i]
+        else:
+            i += 1
+    root = [min(each_set) for each_set in roots]
+    related = [min(each_set) for each_set in roots_and_relateds]
+    related = [n for n in related if n not in root]
+    return root, related
+
+def find_lychrel(maxn, max_reversions):
+    'Lychrel number generator'
+    series = [add_reverse(n, max_reversions*2) for n in range(1, maxn + 1)]
+    roots_and_relateds = [s for s in series if len(s) > max_reversions]
+    return split_roots_from_relateds(roots_and_relateds)
+
+
+if __name__ == '__main__':
+    maxn, reversion_limit = 10000, 500
+    print("Calculations using n = 1..%i and limiting each search to 2*%i reverse-digits-and-adds"
+          % (maxn, reversion_limit))
+    lychrel, l_related = find_lychrel(maxn, reversion_limit)
+    print('  Number of Lychrel numbers:', len(lychrel))
+    print('    Lychrel numbers:', ', '.join(str(n) for n in lychrel))
+    print('  Number of Lychrel related:', len(l_related))
+    #print('    Lychrel related:', ', '.join(str(n) for n in l_related))
+    pals = [x for x in lychrel + l_related  if x == reverse_int(x)]
+    print('  Number of Lychrel palindromes:', len(pals))
+    print('    Lychrel palindromes:', ', '.join(str(n) for n in pals))

Task/Lychrel-numbers/Python/lychrel-numbers-2.py

@@ -0,0 +1,34 @@
+from __future__ import print_function
+
+def rev(n): return int(str(n)[::-1])
+
+def lychel(n, cache = {}):
+    if n in cache: return cache[n]
+
+    n0, r = n, rev(n)
+    res, seen = (True, n), []
+    for i in range(1000):
+        n += r
+        r = rev(n)
+        if n == r:
+            res = (False, 0)
+            break
+        if n in cache:
+            res = cache[n]
+            break
+        seen.append(n)
+
+    for x in seen: cache[x] = res
+    return res
+
+seeds, related, palin = [], [], []
+
+for i in range(1, 1000000):
+    tf, s = lychel(i)
+    if not tf: continue
+    (seeds if i == s else related).append(i)
+    if i == rev(i): palin.append(i)
+
+print("%d Lychel seeds:"%len(seeds), seeds)
+print("%d Lychel related" % len(related))
+print("%d Lychel palindromes:" % len(palin), palin)