feat: quick sort in cpp (doocs#559)

Co-authored-by: willrlzhang <willrlzhang@tencent.com>
Co-authored-by: Yang Libin <contact@yanglibin.info>

Author: 3 people

basic/sorting/QuickSort/Main.cpp

@@ -0,0 +1,80 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+void printvec( const vector<int> &vec, const string &strbegin = "", const string &strend = "" )
+{
+	cout << strbegin << endl;
+	for ( auto val : vec )
+	{
+		cout << val << "\t";
+	}
+
+	cout << endl;
+	cout << strend << endl;
+}
+
+
+int partition( vector<int> & vec, int left, int right )
+{
+	if ( left >= right )
+	{
+		return left;
+	}
+
+	int base = vec[left];
+	while ( left < right )
+	{
+		while ( left < right && vec[right] >= base )
+		{
+			right--;
+		}
+		if ( left >= right )
+		{
+			break;
+		}
+
+		vec[left] = vec[right];
+
+		while ( left < right && vec[left] <= base )
+		{
+			left++;
+		}
+
+		if ( left >= right )
+		{
+			break;
+		}
+
+		vec[right] = vec[left];
+	}
+
+	vec[left] = base;
+	return left;
+}
+
+
+void quicksort( vector<int> & vec, int left, int right )
+{
+	if ( left >= right )
+	{
+		return;
+	}
+
+	int idx = partition( vec, left, right );
+	quicksort( vec, left, idx - 1 );
+	quicksort( vec, idx + 1, right );
+}
+
+
+int main( void )
+{
+	vector<int> vec = { 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
+	printvec( vec );
+	quicksort( vec, 0, vec.size() - 1 );
+	printvec( vec, "after insert sort" );
+	return 0;
+}
+
+
+

basic/sorting/QuickSort/README.md

@@ -288,4 +288,85 @@ fn main() -> io::Result<()> {
 }
 ```
 
+### **C++**
+
+```cpp
+#include <iostream>
+#include <vector>
+
+using namespace std;
+void printvec( const vector<int> &vec, const string &strbegin = "", const string &strend = "" )
+{
+	cout << strbegin << endl;
+	for ( auto val : vec )
+	{
+		cout << val << "\t";
+	}
+
+	cout << endl;
+	cout << strend << endl;
+}
+
+
+int partition( vector<int> & vec, int left, int right )
+{
+	if ( left >= right )
+	{
+		return left;
+	}
+
+	int base = vec[left];
+	while ( left < right )
+	{
+		while ( left < right && vec[right] >= base )
+		{
+			right--;
+		}
+		if ( left >= right )
+		{
+			break;
+		}
+
+		vec[left] = vec[right];
+
+		while ( left < right && vec[left] <= base )
+		{
+			left++;
+		}
+
+		if ( left >= right )
+		{
+			break;
+		}
+
+		vec[right] = vec[left];
+	}
+
+	vec[left] = base;
+	return left;
+}
+
+
+void quicksort( vector<int> & vec, int left, int right )
+{
+	if ( left >= right )
+	{
+		return;
+	}
+
+	int idx = partition( vec, left, right );
+	quicksort( vec, left, idx - 1 );
+	quicksort( vec, idx + 1, right );
+}
+
+
+int main( void )
+{
+	vector<int> vec = { 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 };
+	printvec( vec );
+	quicksort( vec, 0, vec.size() - 1 );
+	printvec( vec, "after insert sort" );
+	return 0;
+}
+```
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