Add 归并排序.cpp

归并排序.cpp

@@ -0,0 +1,65 @@
+7.3 代码 
+#include<stdio.h>
+#include<assert.h>
+#include<stdlib.h> 
+#define ArrLen 20
+void printList(int arr[], int len) 
+{
+	int i;
+	for (i = 0; i < len; i++) 
+	{
+		printf("%d\t", arr[i]);
+	}
+}
+void merge(int arr[], int start, int mid, int end) 
+{
+	int result[ArrLen];
+	int k = 0;
+	int i = start;
+	int j = mid + 1;
+	while (i <= mid && j <= end) 
+	{
+		if (arr[i] < arr[j])
+		{
+			result[k++] = arr[i++];
+        }
+		else{
+			result[k++] = arr[j++];
+        }
+	}
+	if (i == mid + 1) 
+	{
+		while(j <= end)
+			result[k++] = arr[j++];
+	}
+	if (j == end + 1) 
+	{
+		while (i <= mid)
+			result[k++] = arr[i++];
+	}
+	for (j = 0, i = start ; j < k; i++, j++) 
+	{
+		arr[i] = result[j];
+	}
+}
+ 
+void mergeSort(int arr[], int start, int end) 
+{
+	if (start >= end)
+		return;
+	int mid = ( start + end ) / 2;
+	mergeSort(arr, start, mid);
+	mergeSort(arr, mid + 1, end);
+	merge(arr, start, mid, end);
+}
+ 
+int main()
+{
+	int arr[] = {22, 34, 3, 32, 82, 55, 89, 50, 37, 5, 64, 35, 9, 70};
+	mergeSort(arr, 0, 13);
+	printList(arr, 14); 
+	return 0;
+}
+
+7.4 运行时间
+0.02142s