maxHeap.cpp

maxHeap.cpp

@@ -0,0 +1,68 @@
+#include<iostream>
+#include <random>
+using namespace std;
+
+inline int left(int i)//左子树
+{
+	return i << 1;
+}
+inline int right(int i)//右子树
+{
+	return (i << 1) + 1;
+}
+inline int parent(int i)//父节点
+{
+	return i >> 1;
+}
+
+void maintenance(int *a,int i,int size)//维护堆的性质
+{
+	int l = left(i)-1,r=right(i)-1;
+	--i;
+	int large = i;
+	if (l < size && a[l] > a[i])
+		large = l;
+	if (r < size && a[r] > a[large])
+		large = r;
+	if (large!=i)
+	{
+		a[i] ^= a[large];
+		a[large] ^= a[i];
+		a[i] ^= a[large];//异或交换元素无需额外空间
+		if (large<=(size>>1))
+			maintenance(a, large+1, size);//这儿是large+1
+	}
+}
+void build(int *a, int size)//建堆，建堆得同时维护堆
+{
+	for (int i = (size >> 1); i >= 1; --i)
+		maintenance(a, i, size);
+}
+void heapSort(int *a, int size)
+{
+	build(a, size);
+	for (int i = size-1; i >= 1;--i)
+	{
+		a[i] ^= a[0];
+		a[0] ^= a[i];
+		a[i] ^= a[0];//交换堆顶和最后一个元素
+		--size;
+		maintenance(a, 1, size);
+	}
+}
+int main()
+{
+	uniform_int_distribution<int>u(-100, 100);
+	default_random_engine e;
+	int a[100] = { 0 };
+	for (int i = 0; i < 100; ++i)
+		a[i] = u(e);
+	int size = sizeof a / sizeof (int);
+	heapSort(a, size);
+	for (auto &i : a)
+		cout << i << " ";
+	cout << endl;
+	getchar();
+	getchar();
+	return 0;
+}