アイデア:
ダブルポインターを使用して並べ替える
コード:
# include<iostream>
# include<cstdio>
# include<cstring>
# include<algorithm>
using namespace std;
const int N = 100010;
int n;
int q[N],tmp[N];
void merge_sort(int l,int r)
{
if(l >= r) return;
int mid = l + r >> 1;
merge_sort(l,mid);
merge_sort(mid + 1,r);
int k = 0,i = l,j = mid + 1;
while(i <= mid && j <= r)
{
if(q[i] < q[j]) tmp[k++] = q[i++];
else tmp[k++] = q[j++];
}
while(i <= mid) tmp[k++] = q[i++];
while(j <= r) tmp[k++] = q[j++];
for(i = l,j = 0;i <= r;j++,i++) q[i] = tmp[j];
}
int main()
{
scanf("%d",&n);
for(int i = 0;i < n;i++)
{
scanf("%d",&q[i]);
}
merge_sort(0,n - 1);
for(int i = 0;i < n;i++)
{
printf("%d ",q[i]);
}
return 0;
}