合併排序算法實例程序（C語言）

合併排序算法C語言實例程序，如下圖所示：

#include <stdio.h>

int a[20], b[20], n;

void merging(int low, int mid, int high) {
int l1,l2,i;

for(l1 = low, l2 = mid + 1, i = low; l1 <= mid && l2 <= high; i++){
if(a[l1] <= a[l2])
b[i] = a[l1++];
else
b[i] = a[l2++];
}

while(l1 <= mid)
b[i++] = a[l1++];

while(l2 <= high)
b[i++] = a[l2++];

for(i = low; i <= high; i++)
a[i] = b[i];
}

void sort(int low,int high) {
int mid;

if(low < high) {
mid = (low+high) / 2;
sort(low, mid);
sort(mid+1, high);
merging(low, mid, high);
}
else {
return;
}

}

int main() {
int i;

printf("Enter N ");
scanf("%d",&n);

printf("Enter elements\n");

for(i = 1; i <= n; i++)
scanf("%d",& a[i]);

sort(1,n);

printf("After sorting\n");

for(i = 1; i <= n; i++)
printf("%d\n", a[i]);
}