From 2ebf6f7b0c0dbc2f732322f4ab00492fd75ec9ee Mon Sep 17 00:00:00 2001
From: xhl <2682950883@qq.com>
Date: Fri, 6 May 2022 10:45:29 +0800
Subject: [PATCH 1/2] finish all

---
 main.cpp | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/main.cpp b/main.cpp
index d76cce7..478e11e 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,6 +3,7 @@
 #include <variant>
 
 // 请修复这个函数的定义：10 分
+template <typename T>
 std::ostream &operator<<(std::ostream &os, std::vector<T> const &a) {
     os << "{";
     for (size_t i = 0; i < a.size(); i++) {
@@ -14,21 +15,80 @@ std::ostream &operator<<(std::ostream &os, std::vector<T> const &a) {
     return os;
 }
 
-// 请修复这个函数的定义：10 分
+template <bool B, class T1, class T2>
+struct _if;
+
+template <class T1,class T2>
+struct _if<true, T1, T2>
+{
+    using value = T1;
+};
+
+template <class T1,class T2>
+struct _if<false, T1, T2>
+{
+    using value = T2;
+};
+
 template <class T1, class T2>
+struct bigger_size
+{
+    using value = typename _if< bool(sizeof(T1)>sizeof(T2)), T1, T2 >::value;
+};
+
+// 请修复这个函数的定义：10 分
+template <class T1, class T2, class T0 = typename bigger_size<T1,T2>::value>
 std::vector<T0> operator+(std::vector<T1> const &a, std::vector<T2> const &b) {
     // 请实现列表的逐元素加法！10 分
     // 例如 {1, 2} + {3, 4} = {4, 6}
+    const size_t s = std::min(a.size(), b.size());
+    std::vector<T0> v(s);
+    for(int i=0; i<s; i++){
+        v[i] = a[i] + b[i];
+    }
+    return v;
+}
+
+template<class T1, class T2>
+std::variant<T1, T2> 
+operator+(std::variant<T1,T2> const &a, T2 const& b){
+    std::variant<T1, T2> v;
+    if(a.index()==0)
+        v = std::get<0>(a) + b;
+    else
+        v = std::get<1>(a) + b;
+    return v;
+}
+
+template<class T1, class T2>
+std::variant<T1, T2> 
+operator+(std::variant<T1,T2> const &a, T1 const& b){
+    std::variant<T1, T2> v;
+    if(a.index()==0)
+        v = std::get<0>(a) + b;
+    else
+        v = std::get<1>(a) + b;
+    return v;
 }
 
 template <class T1, class T2>
 std::variant<T1, T2> operator+(std::variant<T1, T2> const &a, std::variant<T1, T2> const &b) {
     // 请实现自动匹配容器中具体类型的加法！10 分
+    std::variant<T1, T2> v;
+    if(b.index()==0)
+        v = a + std::get<0>(b);
+    else
+        v = a + std::get<1>(b);
+    return v;
 }
 
-template <class T1, class T2>
-std::ostream &operator<<(std::ostream &os, std::variant<T1, T2> const &a) {
+template <class T0, class ...T>
+std::ostream &operator<<(std::ostream &os, std::variant<T0, T...> const &a) {
     // 请实现自动匹配容器中具体类型的打印！10 分
+    std::visit([&](const auto& t){
+        os << t;
+    }, a);
+    return os;
 }
 
 int main() {

From c02d0ed35bf497c0c1913e9b6d1f79141eea1bad Mon Sep 17 00:00:00 2001
From: xhl <2682950883@qq.com>
Date: Fri, 6 May 2022 10:53:45 +0800
Subject: [PATCH 2/2] optimize the vector plus

---
 main.cpp | 26 +++-----------------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/main.cpp b/main.cpp
index 478e11e..17cd318 100644
--- a/main.cpp
+++ b/main.cpp
@@ -15,32 +15,12 @@ std::ostream &operator<<(std::ostream &os, std::vector<T> const &a) {
     return os;
 }
 
-template <bool B, class T1, class T2>
-struct _if;
-
-template <class T1,class T2>
-struct _if<true, T1, T2>
-{
-    using value = T1;
-};
-
-template <class T1,class T2>
-struct _if<false, T1, T2>
-{
-    using value = T2;
-};
-
-template <class T1, class T2>
-struct bigger_size
-{
-    using value = typename _if< bool(sizeof(T1)>sizeof(T2)), T1, T2 >::value;
-};
-
 // 请修复这个函数的定义：10 分
-template <class T1, class T2, class T0 = typename bigger_size<T1,T2>::value>
-std::vector<T0> operator+(std::vector<T1> const &a, std::vector<T2> const &b) {
+template <class T1, class T2>
+auto operator+(std::vector<T1> const &a, std::vector<T2> const &b) {
     // 请实现列表的逐元素加法！10 分
     // 例如 {1, 2} + {3, 4} = {4, 6}
+    using T0 = decltype(T1()+T2());
     const size_t s = std::min(a.size(), b.size());
     std::vector<T0> v(s);
     for(int i=0; i<s; i++){