problem 3 4 5 6 6 in julia

1 files changed, 37 insertions, 0 deletions

diff --git a/julia/007-10001st_prime.jl b/julia/007-10001st_prime.jl
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+###
+# 10001st prime
+# Problem 7
+#
+# By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th
+# prime is 13.
+# What is the 10 001st prime number?
+###
+
+using Printf
+using Base.Iterators
+
+function is_prime(n)
+    if n == 2 || n == 3 || n == 5
+        return true
+    end
+    if n % 2 == 0 || n % 3 == 0 || n % 5 == 0
+        return false
+    end
+    for d in 6:6:Int64(ceil(sqrt(n)) + 1)
+        if n % (d - 1) == 0 || n % (d + 1) == 0
+            return false
+        end
+    end
+    true
+end
+
+counter = 0
+for n in Iterators.countfrom(2)
+    if is_prime(n)
+        global counter += 1
+        @printf "%5d: %d\n" counter n
+    end
+    if counter == 10_001
+        break
+    end
+end