feat: basic fast io for C++

cpp/a.cpp

@@ -4,9 +4,29 @@
 #pragma GCC optimize("Ofast")
 #pragma GCC optimization("unroll-loops")
 
+#define N 3
+
 using namespace std;
 
 int main()
 {
-    cout << "Hello, C++!\n";
+    // faster IO
+    ios::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    int sum = 0;
+    int nums[N];
+
+    for (int i = 0; i < N; i++)
+    {
+        cin >> nums[i];
+        sum += nums[i];
+
+        cout << nums[i];
+
+        if (i < N - 1)
+            cout << " + ";
+    }
+
+    cout << " = " << sum << "\n";
 }

cpp/cpp.justfile

@@ -5,4 +5,4 @@
     ./cpp/a < ./input.txt
 
 @bench-cpp: build-cpp
-    hyperfine './cpp/a < ./input.txt'
+    hyperfine './cpp/a < ./input.txt'