feat: util/fn/digits.hpp

arumakan1727 · Aug 5, 2023 · 9c8f324 · 9c8f324
1 parent 9fb632e
commit 9c8f324
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/src/armkn/util/fn/digits.hpp b/src/armkn/util/fn/digits.hpp
@@ -0,0 +1,19 @@
+#pragma once
+#include <vector>
+#include "../alias/stdint.hpp"
+
+/// 実際の表記と順序が逆になるので注意;
+/// `digits(123)` => `{3, 2, 1}`
+template <u32 BASE = 10>
+inline auto digits(u64 n) -> std::vector<int> {
+  static_assert(BASE >= 2);
+  if (n == 0) return {0};
+  std::vector<int> d;
+  d.reserve(64);
+  while (n > 0) {
+    d.push_back(n % BASE);
+    n /= BASE;
+  }
+  d.shrink_to_fit();
+  return d;
+}