Add .gitignore and base hello world code

Author: Sirivasv

.gitignore

@@ -0,0 +1,55 @@
+# Compiled object files
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Compiled Static libraries
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+*.elf
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
+
+# CMake build folders
+/build/
+[Cc]MakeCache.txt
+[Cc]MakeFiles/
+cmake_install.cmake
+Makefile
+
+# Qt Creator
+*.pro.user
+*.qmake.stash
+
+# Visual Studio Code
+.vscode/
+*.ilk
+
+# CLion
+.idea/
+cmake-build-*/
+
+# Other
+*.log
+*.tmp
+*.swp
+*~
+.DS_Store
+Thumbs.db

simple_cpp/input.in

@@ -0,0 +1,2 @@
+5
+6

simple_cpp/main.cpp

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+#include <iostream>
+using namespace std;
+
+int main() {
+    cin.tie(0); ios_base::sync_with_stdio(0);
+    int a, b;
+    cin >> a >> b;
+    cout << "Hello, Tsinghua SSSP!" << endl;
+    cout << "The sum of " << a << " and " << b << " is " << a + b << "." << endl;
+    return 0;
+}