Merge pull request #2915 from ash/master

Week 89 Task 1 and an Advent blog post

1 files changed, 29 insertions, 0 deletions

diff --git a/challenge-089/ash/cpp/ch-1.cpp b/challenge-089/ash/cpp/ch-1.cpp
new file mode 100644
index 0000000000..b2500a4630
--- /dev/null
+++ b/challenge-089/ash/cpp/ch-1.cpp
@@ -0,0 +1,29 @@
+// Compile as:
+// $ g++ -std=c++17 ch-1.cpp
+
+// Test run:
+// $ ./a.out 100
+// 13015
+
+#include <iostream>
+#include <numeric>
+#include <sstream>
+
+using namespace std;
+
+int main(int argc, char** argv) {
+    int n = 3;
+    if (argc != 1) {
+        stringstream input(argv[1]);
+        input >> n;
+    }
+
+    int s = 0;
+    for (int x = 1; x <= n; x++) {
+        for (int y = x + 1; y <= n; y++) {
+            s += gcd(x, y);
+        }
+    }
+
+    cout << s << endl;
+}