update

src/P1969/P1969.cpp

@@ -0,0 +1,44 @@
+#include <iostream>
+#include <type_traits>
+
+
+using ull = unsigned long long;
+static ull a, b, ans, n;
+
+template<class T>
+class ReadNumber{
+    char c;
+    T w,n;
+public:
+    ReadNumber&operator>>(T &t){
+        c=(char)0,w=1,n=0;
+        while(!isdigit(c)){
+            if constexpr (std::is_signed_v<T>){
+                if(c=='-')w=-1;
+            }
+            c=getchar();
+        }
+        while(isdigit(c)){
+            n=n*10+(c-'0');
+        }
+        t = n*w;
+        return *this;
+    }
+};
+static ReadNumber<ull> readull;
+// static auto &is = std::cin;
+static auto &is = readull;
+static auto &os = std::cout;
+
+
+int main(){
+    is>>n;
+    for(size_t i{0};i<n;i++){
+        is>>b;
+        if(a<b){
+            ans+=b-a;
+        }
+        a=b;
+    }
+    os<<ans<<'\n';
+}