From d4541a3f800c476d51f649d530b20610d2bced83 Mon Sep 17 00:00:00 2001
From: Enriquefft <enriquefft2001@gmail.com>
Date: Sat, 13 Jul 2024 23:11:25 -0500
Subject: [PATCH] added modulo exponentiation

---
 src/ModuloExponentiation.cpp | 32 ++++++++++++++++++++++
 src/main.cpp                 | 53 ------------------------------------
 2 files changed, 32 insertions(+), 53 deletions(-)
 create mode 100644 src/ModuloExponentiation.cpp
 delete mode 100644 src/main.cpp

diff --git a/src/ModuloExponentiation.cpp b/src/ModuloExponentiation.cpp
new file mode 100644
index 0000000..d736d9e
--- /dev/null
+++ b/src/ModuloExponentiation.cpp
@@ -0,0 +1,32 @@
+#include <cstdint>
+using ll = intmax_t;
+using ull = uintmax_t;
+
+constexpr ll MODULO = 1000000007;
+
+// exponent is very large
+// modulo is prime (1e9 + 7)
+// base is always 2
+
+/// @brief Binary Exponentiation with modulo
+/// @param expo exponent
+/// @param base base (default: 2)
+/// @param modulo modulo
+template <bool USE_FERMAT_LITTLE_THEOREM = false>
+constexpr auto bin_mod_exp(ll expo, ll base = 2, ll modulo = MODULO) -> ll {
+
+  if constexpr (USE_FERMAT_LITTLE_THEOREM) {
+    expo %= (modulo - 1);
+  }
+
+  ll res = 1;
+
+  while (expo > 0) {
+    if (expo & 1LL) {
+      res = (res * base) % modulo;
+    }
+    base = (base * base) % modulo;
+    expo >>= 1LL;
+  }
+  return res;
+}
diff --git a/src/main.cpp b/src/main.cpp
deleted file mode 100644
index 460c2b6..0000000
--- a/src/main.cpp
+++ /dev/null
@@ -1,53 +0,0 @@
-#include <Texture.hpp>
-#include <Window.hpp>
-#include <raylib.h>
-
-#if defined(_WIN32)
-#define NOGDI  // All GDI defines and routines
-#define NOUSER // All USER defines and routines
-#endif
-
-#include <spdlog/spdlog.h>
-
-#if defined(_WIN32) // raylib uses these names as function parameters
-#undef near
-#undef far
-#endif
-
-constexpr int TARGET_FPS = 60;
-
-auto main() -> int {
-
-  constexpr int SCREEN_WIDTH = 800;
-  constexpr int SCREEN_HEIGHT = 450;
-
-  constexpr int TEXT_X_POS = 190;
-  constexpr int TEXT_Y_POS = 200;
-  constexpr int TEXT_FONT_SIZE = 20;
-
-  raylib::Window window(SCREEN_WIDTH, SCREEN_HEIGHT,
-                        "raylib-cpp - basic window");
-  raylib::Texture logo(ASSETS_PATH "dogo.png");
-
-  SetTargetFPS(TARGET_FPS);
-
-  spdlog::info("Started drawing");
-
-  while (!window.ShouldClose()) {
-    BeginDrawing();
-
-    window.ClearBackground(RAYWHITE);
-
-    // Object methods.
-    logo.Draw(SCREEN_WIDTH / 2 - logo.GetWidth() / 2,
-              SCREEN_HEIGHT / 2 - logo.GetHeight() / 2);
-
-    DrawText("Congrats! You created your first window!", TEXT_X_POS, TEXT_Y_POS,
-             TEXT_FONT_SIZE, LIGHTGRAY);
-
-    EndDrawing();
-  }
-  spdlog::info("Finished drawing");
-
-  return 0;
-}