Problem:
Set Union

Find the union of two sets $A = \{a_0, a_1, ..., a_{n-1}\}$ and $B = \{b_0, b_1, ..., b_{m-1}\}$.

Input

The input is given in the following format.

$n$
$a_0 \; a_1 \; ... \; a_{n-1}$
$m$
$b_0 \; b_1 \; ... \; b_{m-1}$

Elements of $A$ and $B$ are given in ascending order respectively. There are no duplicate elements in each set.

Output

Print elements in the union in ascending order. Print an element in a line.

Constraints

$1 \leq n, m \leq 200,000$

$0 \leq a_0 < a_1 < ... < a_{n-1} \leq 10^9$

$0 \leq b_0 < b_1 < ... < b_{m-1} \leq 10^9$

Sample Input 1

3
1 5 8
2
5 9

Sample Output 1

1
5
8
9

Solution in C (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>
#define MAX 200000
#define INF 2000000000

int compare_int(const void *a,const void *b){
	return *(int*)a-*(int*)b;
}

int main(){
	int n,m;
	int a[MAX+1];
	int b[MAX+1];
	int j=0,k=0;
	
	scanf("%d",&n);
	for(int i=0;i<n;i++)
		scanf("%d",&a[i]);
	a[n]=INF;
	
	qsort(a,n,sizeof(int),compare_int);
	
	scanf("%d",&m);
	for(int i=0;i<m;i++)
		scanf("%d",&b[i]);
	b[m]=INF;
	
	qsort(b,m,sizeof(int),compare_int);
	
	for(int i=0;i<n+m;i++){
		if(a[j]==INF && b[k]==INF)break;
	
		if(a[j] < b[k])
			printf("%d\n",a[j++]);

		else if(a[j] > b[k])
			printf("%d\n",b[k++]);

		else if(a[j]==b[k]){
			printf("%d\n",a[j]);
			int temp=a[j];
			while(a[j]==temp)j++;
			while(b[k]==temp)k++;
		}
	}
	
	return 0;
	
}