Binary GCD

detel · Jul 15, 2015 · a5583a7 · a5583a7
1 parent 1eec6b6
commit a5583a7
Showing 1 changed file with 25 additions and 0 deletions.
diff --git a/Binary GCD.py b/Binary GCD.py
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+def gcd_bin(u, v):
+    u, v = abs(u), abs(v)
+    if u < v:
+        u, v = v, u
+    if v == 0:
+        return u
+
+    k = 1
+    while u & 1 == 0 and v & 1 == 0:
+        u >>= 1
+        v >>= 1
+        k <<= 1
+
+    t = -v if u & 1 else u
+    while t:
+        while t & 1 == 0:
+            t >>= 1
+        if t > 0:
+            u = t
+        else:
+            v = -t
+        t = u - v
+    return u*k
+
+print gcd_bin(2334680,789785665)