#include <stdio.h>
#include <stdlib.h>
void merge(int arr[], int left, int mid, int right) {
int i, j, k;
int n1 = mid - left + 1;
int n2 = right - mid;
int L[n1], R[n2];
for (i = 0; i < n1; i++)
L[i] = arr[left + i];
for (j = 0; j < n2; j++)
R[j] = arr[mid + 1 + j];
i = 0;
j = 0;
k = left;
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 left, int right) {
if (left < right) {
int mid = left + (right - left) / 2;
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
}
int main() {
int arr1[5] = { 5, 4, 3, 2, 1 };
int n1 = sizeof(arr1) / sizeof(arr1[0]);
printf("原数组1:");
for (int i = 0; i < n1; i++)
printf("%d ", arr1[i]);
printf("\n");
mergeSort(arr1, 0, n1 - 1);
printf("排序后1:");
for (int i = 0; i < n1; i++)
printf("%d ", arr1[i]);
printf("\n\n");
int arr2[5] = { 5, 4, 3 };
int n2 = sizeof(arr2) / sizeof(arr2[0]);
printf("原数组2:");
for (int i = 0; i < n2; i++)
printf("%d ", arr2[i]);
printf("\n");
mergeSort(arr2, 0, n2 - 1);
printf("排序后2:");
for (int i = 0; i < n2; i++)
printf("%d ", arr2[i]);
printf("\n\n");
int arr3[5] = { 1, 1, 1, 1, 1 };
int n3 = sizeof(arr3) / sizeof(arr3[0]);
printf("原数组3:");
for (int i = 0; i < n3; i++)
printf("%d ", arr3[i]);
printf("\n");
mergeSort(arr3, 0, n3 - 1);
printf("排序后3:");
for (int i = 0; i < n3; i++)
printf("%d ", arr3[i]);
printf("\n\n");
return 0;
}