add solutions

1 files changed, 40 insertions, 0 deletions

diff --git a/challenge-251/witawayar/cpp/ch-1.cpp b/challenge-251/witawayar/cpp/ch-1.cpp
new file mode 100644
index 0000000000..acc8331116
--- /dev/null
+++ b/challenge-251/witawayar/cpp/ch-1.cpp
@@ -0,0 +1,40 @@
+// g++ -Wall -Wextra -Wpedantic -std=c++17 cpp/ch-1.cpp
+#include <algorithm>  // transform
+#include <iostream>   // cout
+#include <numeric>    // accumulate
+#include <sstream>    // stringstream
+#include <vector>
+
+int fun(std::vector<int> const& ints) {
+    std::vector<int> out;
+    std::transform(ints.cbegin(), ints.cend(),
+                   ints.crbegin(), std::back_inserter(out),
+                   [](const int& a, const int& b) {
+                       return std::stoi(std::to_string(a) + std::to_string(b)); });
+    std::size_t out_size = out.size();
+    int sum = std::accumulate(out.cbegin(), out.cbegin() + out_size / 2, 0);
+    if (out_size % 2 != 0)
+        sum += ints[ints.size() / 2];
+
+    return sum;
+}
+
+int main(void) {
+    // Tests
+    std::vector<std::pair<std::vector<int>, int>> tests = {
+        {{6, 12, 25, 1}, 1286},
+        {{10, 7, 31, 5, 2, 2}, 489},
+        {{1, 2, 10}, 112}
+    };
+
+    for (const auto& [input, expected_output] : tests) {
+        int got = fun(input);
+        if (got != expected_output) {
+            std::stringstream error_msg;
+            error_msg << "Expected " << expected_output << ", got " << got;
+            throw std::runtime_error(error_msg.str());
+        }
+    }
+
+    std::cout << "done-testing, success\n";
+}