Data commit

Task/Prime-triangle/Python/prime-triangle.py

@@ -0,0 +1,49 @@
+from numpy import array
+# for Rosetta Code by MG - 20230312
+def is_prime(n: int) -> bool:
+    assert n < 64
+    return ((1 << n) & 0x28208a20a08a28ac) != 0
+
+def prime_triangle_row(a: array, start: int, length: int) -> bool:
+    if length == 2:
+        return is_prime(a[0] + a[1])
+    for i in range(1, length - 1, 1):
+        if is_prime(a[start] + a[start + i]):
+            a[start + i], a[start + 1] = a[start + 1], a[start + i]
+            if prime_triangle_row(a, start + 1, length - 1):
+                return True
+            a[start + i], a[start + 1] = a[start + 1], a[start + i]
+    return False
+
+def prime_triangle_count(a: array, start: int, length: int) -> int:
+    count: int = 0
+    if length == 2:
+        if is_prime(a[start] + a[start + 1]):
+            count += 1
+    else:
+        for i in range(1, length - 1, 1):
+            if is_prime(a[start] + a[start + i]):
+                a[start + i], a[start + 1] = a[start + 1], a[start + i]
+                count += prime_triangle_count(a, start + 1, length - 1)
+                a[start + i], a[start + 1] = a[start + 1], a[start + i]
+    return count
+
+def print_row(a: array):
+    if a == []:
+        return
+    print("%2d"% a[0], end=" ")
+    for x in a[1:]:
+        print("%2d"% x, end=" ")
+    print()
+
+for n in range(2, 21):
+    tr: array = [_ for _ in range(1, n + 1)]
+    if prime_triangle_row(tr, 0, n):
+        print_row(tr)
+print()
+for n in range(2, 21):
+    tr: array = [_ for _ in range(1, n + 1)]
+    if n > 2:
+        print(" ", end="")
+    print(prime_triangle_count(tr, 0, n), end="")
+print()