2021.5.28 add qsort

sort.cpp

+#include <iostream>
+#include <utility>
+
+/// <summary>
+/// 快速排序标准实现
+/// 排序范围为 [left, right)
+/// 利用 operator lt
+/// </summary>
+template <typename T>
+void quick_sort(T* x, int left, int right)
+{
+	if (right - left <= 1)
+		return;
+	T pivot = x[left];   //copy construct
+	int p = left;
+	for (int i = left + 1; i < right; i++) {
+		if (x[i] < pivot) {
+			p++;
+			std::swap(x[p], x[i]);
+		}
+	}
+	std::swap(x[left], x[p]);
+	quick_sort(x, left, p);
+	quick_sort(x, p + 1, right);
+}
+
+
+#include <algorithm>
+#include <time.h>
+#include <cstdlib>
+using namespace std;
+
+int main()
+{
+	constexpr int N = 100;
+	int x[N];
+	srand(time(NULL));
+	for (int i = 0; i < N; i++) {
+		x[i] = rand() % 1000;
+	}
+	quick_sort(x, 0, N);
+	for (int i = 0; i < N; i++) {
+		cout << x[i] << ' ';
+	}
+	cout << endl;
+	return 0;
+}