add: graphs et rushs

1 files changed, 15 insertions, 0 deletions

diff --git a/graphs/cpp/lookup_table/fibo.cc b/graphs/cpp/lookup_table/fibo.cc
new file mode 100644
index 0000000..80b72b1
--- /dev/null
+++ b/graphs/cpp/lookup_table/fibo.cc
@@ -0,0 +1,15 @@
+#include "fibo.hh"
+
+long Fibo::operator()(int x)
+{
+    if (x <= 1)
+        return x;
+
+    std::optional<long> opt_lookup_table = lookup_table_.get(x);
+    if (opt_lookup_table)
+        return *opt_lookup_table;
+
+    auto res = (*this)(x - 1) + (*this)(x - 2);
+    lookup_table_.set(x, res);
+    return res;
+}