C实现归并排序

先放代码

#include<stdio.h>
void printList(int arr[], int len) {

int i;

for (i = 0; i < len; i++) {

printf("%d", arr[i]);

}

}

void merge(int arr[], int start, int mid, int end) {

int result[end+1];

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 n;

scanf("%d",&n);

int a[n];

for(int i = 0;i<n;i++)

scanf("%d ",&a[i]);

mergeSort(a, 0, n-1);

printList(a, n);

return 0;

}