From f0881305402f3dff56f99fcc4cbc8b615581b780 Mon Sep 17 00:00:00 2001
From: Igor Pashev <pashev.igor@gmail.com>
Date: Sun, 28 Aug 2022 15:40:21 +0200
Subject: C, Haskell, Python, Fortran

---
 mendeleev.py | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 mendeleev.py

(limited to 'mendeleev.py')

diff --git a/mendeleev.py b/mendeleev.py
new file mode 100644
index 0000000..b026ab1
--- /dev/null
+++ b/mendeleev.py
@@ -0,0 +1,102 @@
+import sys
+
+
+# fmt: off
+ELEMENTS = [
+  "Ac", "Ag", "Al", "Am", "Ar", "As", "At", "Au", "B", "Ba", "Be", "Bh",
+  "Bi", "Bk", "Br", "C", "Ca", "Cd", "Ce", "Cf", "Cl", "Cm", "Cn", "Co",
+  "Cr", "Cs", "Cu", "Db", "Ds", "Dy", "Er", "Es", "Eu", "F", "Fe", "Fl",
+  "Fm", "Fr", "Ga", "Gd", "Ge", "H", "He", "Hf", "Hg", "Ho", "Hs", "I",
+  "In", "Ir", "K", "Kr", "La", "Li", "Lr", "Lu", "Lv", "Mc", "Md", "Mg",
+  "Mn", "Mo", "Mt", "N", "Na", "Nb", "Nd", "Ne", "Nh", "Ni", "No", "Np",
+  "O", "Og", "Os", "P", "Pa", "Pb", "Pd", "Pm", "Po", "Pr", "Pt", "Pu",
+  "Ra", "Rb", "Re", "Rf", "Rg", "Rh", "Rn", "Ru", "S", "Sb", "Sc", "Se",
+  "Sg", "Si", "Sm", "Sn", "Sr", "Ta", "Tb", "Tc", "Te", "Th", "Ti", "Tl",
+  "Tm", "Ts", "U", "V", "W", "Xe", "Y", "Yb", "Zn", "Zr"
+]
+# fmt: on
+
+elements = [el.lower() for el in ELEMENTS]
+
+
+def search(start, length, shift, char):
+    upper = start + length
+    lower = start
+    while lower < upper:
+        mid = int((lower + upper) / 2)
+        if elements[mid][shift] < char:
+            lower = mid + 1
+        else:
+            upper = mid
+
+    if lower == start + length:
+        return (0, 0)
+
+    if elements[lower][shift] != char:
+        return (0, 0)
+
+    upper = start + length
+    start = lower
+    while lower < upper:
+        mid = int((lower + upper) / 2)
+        if char < elements[mid][shift]:
+            upper = mid
+        else:
+            lower = mid + 1
+
+    length = upper - start
+
+    return (start, length)
+
+
+def divide(tail):
+    result = []
+
+    start = 0
+    length = len(ELEMENTS)
+    shift = 0
+
+    while shift < len(tail):
+        start, length = search(start, length, shift, tail[shift])
+        if length == 0:
+            break
+
+        shift += 1
+        if len(ELEMENTS[start]) == shift:
+            result.append((ELEMENTS[start], tail[shift:]))
+            start += 1
+            length -= 1
+
+    return result or [("?", tail[1:])]
+
+
+def advance(els, tail):
+    return [(els + [e], t) for (e, t) in divide(tail)]
+
+
+def explode(word):
+    result = [([], word.lower())]
+    while True:
+        new = []
+        tail = None
+        for res in result:
+            if res[1]:
+                adv = advance(*res)
+                new.extend(adv)
+                if not tail:
+                    tail = adv[0][1]
+            else:
+                new.append(res)
+
+        result = new
+
+        if not tail:
+            break
+
+    return [els for els, _ in result]
+
+
+for w in sys.argv[1:]:
+    print(w + ":")
+    for f in filter(None, explode(w)):
+        print(" " + " ".join(f))
-- 
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