From d30a94ca6129302823b1bc91945cb8461c1e3e73 Mon Sep 17 00:00:00 2001
From: shogo314 <shg.kawasome@gmail.com>
Date: Sun, 11 Feb 2024 12:44:50 +0900
Subject: [PATCH] add assign

---
 cpp/rolling-hash.hpp | 72 ++++++++++++++++++++++++++++++++++++++------
 cpp/traits.hpp       | 19 ++++++++++++
 2 files changed, 82 insertions(+), 9 deletions(-)
 create mode 100644 cpp/traits.hpp

diff --git a/cpp/rolling-hash.hpp b/cpp/rolling-hash.hpp
index 1e79cb5..f3d174a 100644
--- a/cpp/rolling-hash.hpp
+++ b/cpp/rolling-hash.hpp
@@ -5,6 +5,8 @@
 #include <random>
 #include <cassert>
 
+#include "traits.hpp"
+
 struct RHString;
 
 /**
@@ -116,13 +118,19 @@ struct RHString {
     RHString(RollingHash& rh) : rh(rh), sz(0), hash1(0), hash2(0) {}
     RHString(RollingHash& rh, size_t sz, unsigned long long hash1, unsigned long long hash2) : rh(rh), sz(sz), hash1(hash1), hash2(hash2) {}
     RHString(const RHString& o) : rh(o.rh), sz(o.sz), hash1(o.hash1), hash2(o.hash2) {}
-    template <typename R>
-    RHString(RollingHash& rh, R s) : rh(rh) {
-        using std::begin, std::end;
+    template <class R, class = std::enable_if_t<is_range_v<R>>>
+    RHString(RollingHash& rh, R&& s) : rh(rh) {
+        using std::begin, std::end, std::rbegin, std::rend;
         sz = std::distance(begin(s), end(s));
         hash1 = rh.build(begin(s), end(s)).back();
         hash2 = rh.build(rbegin(s), rend(s)).back();
     }
+    template <class T, class = std::enable_if_t<!is_range_v<T>>>
+    RHString(RollingHash& rh, T x) : rh(rh) {
+        sz = 1;
+        hash1 = x;
+        hash2 = x;
+    }
 
     /**
      * @brief 回文か否か
@@ -150,22 +158,68 @@ struct RHString {
         sz += o.sz;
         return *this;
     }
-    RHString& operator=(const RHString& o) {
+    /**
+     * @brief 再代入する
+     */
+    void assign(const RHString& o) {
         assert(&rh == &o.rh);
         sz = o.sz;
         hash1 = o.hash1;
         hash2 = o.hash2;
-        return *this;
     }
     /**
-     * @brief 文字列などで初期化する
+     * @brief 文字列(std::string)などで再代入する
      */
-    template <typename R>
-    RHString& assign(const R& s) {
+    template <class R, class = std::enable_if_t<is_range_v<R>>>
+    void assign(R&& s) {
         using std::begin, std::end;
         sz = std::distance(begin(s), end(s));
         hash1 = rh.build(begin(s), end(s)).back();
         hash2 = rh.build(rbegin(s), rend(s)).back();
+    }
+    /**
+     * @brief 文字(char)などで再代入する
+     */
+    template <class T, class = std::enable_if_t<not is_range_v<T>>>
+    void assign(T x) {
+        sz = 1;
+        hash1 = x;
+        hash2 = x;
+    }
+    /**
+     * @brief const char*で再代入する
+     */
+    void assign(const char* s) {
+        assign(std::string(s));
+    }
+    /**
+     * @brief 再代入する
+     */
+    RHString& operator=(const RHString& o) {
+        assign(o);
+        return *this;
+    }
+    /**
+     * @brief 文字列(std::string)などで再代入する
+     */
+    template <class R, class = std::enable_if_t<is_range_v<R>>>
+    RHString& operator=(R&& s) {
+        assign(s);
+        return *this;
+    }
+    /**
+     * @brief 文字(char)などで再代入する
+     */
+    template <class T, class = std::enable_if_t<not is_range_v<T>>>
+    RHString& operator=(T x) {
+        assign(x);
+        return *this;
+    }
+    /**
+     * @brief const char*で再代入する
+     */
+    RHString& operator=(const char* s) {
+        assign(s);
         return *this;
     }
     friend RHString operator+(const RHString& t1, const RHString& t2) {
@@ -175,7 +229,7 @@ struct RHString {
     }
     friend bool operator==(const RHString& t1, const RHString& t2) {
         assert(&t1.rh == &t2.rh);
-        return t1.hash1 == t2.hash1 && t1.hash2 == t2.hash2;
+        return t1.sz == t2.sz && t1.hash1 == t2.hash1 && t1.hash2 == t2.hash2;
     }
     friend bool operator!=(const RHString& t1, const RHString& t2) { return !(t1 == t2); }
 };
diff --git a/cpp/traits.hpp b/cpp/traits.hpp
new file mode 100644
index 0000000..590a8c5
--- /dev/null
+++ b/cpp/traits.hpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <iterator>
+#include <type_traits>
+#include <utility>
+
+namespace detail {
+using std::begin, std::end;
+
+template <class T, class = void>
+struct is_range_impl : std::false_type {};
+template <class T>
+struct is_range_impl<T, std::void_t<decltype(begin(std::declval<T&>()), end(std::declval<T&>()))>> : std::true_type {};
+}  // namespace detail
+
+template <class T>
+struct is_range : detail::is_range_impl<T>::type {};
+template <class T>
+inline constexpr bool is_range_v = is_range<T>::value;