C++ Mergesort数组代码怎么写?
时间: 2023-03-14 07:14:08 浏览: 46
归并排序的代码实现非常简单,主要思想是递归地将数组分割成较小的部分,然后将这些部分按顺序合并起来。代码示例如下:def mergesort(arr):
if len(arr) > 1:
mid = len(arr) // 2
L = arr[:mid]
R = arr[mid:]
mergesort(L)
mergesort(R)
i = j = k = 0
while i < len(L) and j < len(R):
if L[i] < R[j]:
arr[k] = L[i]
i+=1
else:
arr[k] = R[j]
j+=1
k+=1
while i < len(L):
arr[k] = L[i]
i+=1
k+=1
while j < len(R):
arr[k] = R[j]
j+=1
k+=1
相关问题
mergesort数组排序 c++
好的,这里是使用归并排序对数组进行排序的示例代码:
```c++
#include <iostream>
using namespace std;
void merge(int arr[], int l, int m, int r) {
int n1 = m - l + 1;
int n2 = r - m;
int L[n1], R[n2];
for (int i = 0; i < n1; i++)
L[i] = arr[l + i];
for (int j = 0; j < n2; j++)
R[j] = arr[m + 1 + j];
int i = 0, j = 0, k = l;
while (i < n1 && j < n2) {
if (L[i] <= R[j]) {
arr[k] = L[i];
i++;
}
else {
arr[k] = R[j];
j++;
}
k++;
}
while (i < n1) {
arr[k] = L[i];
i++;
k++;
}
while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
}
void mergeSort(int arr[], int l, int r) {
if (l >= r)
return;
int m = l + (r - l) / 2;
mergeSort(arr, l, m);
mergeSort(arr, m + 1, r);
merge(arr, l, m, r);
}
int main() {
int arr[] = { 12, 11, 13, 5, 6, 7 };
int n = sizeof(arr) / sizeof(arr[0]);
cout << "Given array is \n";
for (int i = 0; i < n; i++)
cout << arr[i] << " ";
cout << endl;
mergeSort(arr, 0, n - 1);
cout << "\nSorted array is \n";
for (int i = 0; i < n; i++)
cout << arr[i] << " ";
cout << endl;
return 0;
}
```
用c++写归并排序代码
以下是C语言实现归并排序的代码:
```c
#include <stdio.h>
#include <stdlib.h>
// 合并两个有序数组
void merge(int arr[], int left, int mid, int right) {
int i = left, j = mid + 1, k = 0;
int *temp = (int*)malloc((right - left + 1) * sizeof(int));
while (i <= mid && j <= right) {
if (arr[i] < arr[j]) {
temp[k++] = arr[i++];
} else {
temp[k++] = arr[j++];
}
}
while (i <= mid) {
temp[k++] = arr[i++];
}
while (j <= right) {
temp[k++] = arr[j++];
}
for (i = left, k = 0; i <= right; i++, k++) {
arr[i] = temp[k];
}
free(temp);
}
// 归并排序
void mergeSort(int arr[], int left, int right) {
if (left >= right) {
return;
}
int mid = (left + right) / 2;
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
int main() {
int arr[] = {38, 27, 43, 3, 9, 82, 10};
int len = sizeof(arr) / sizeof(int);
mergeSort(arr, 0, len - 1);
for (int i = 0; i < len; i++) {
printf("%d ", arr[i]);
}
return 0;
}
```
在这个示例中,我们使用 `merge()` 函数来合并两个有序数组,使用 `mergeSort()` 函数来递归地将数组分成较小的子数组并进行排序。最后,我们在 `main()` 函数中使用示例数组来测试我们的排序算法。