1029. Median

题目链接;http://pat.zju.edu.cn/contests/pat-a-practise/1029

merge~~~~~~~1. 有序归并；2. 组内归并

merge

// 有序排序，首选merge，sort在基本线性的序列中退化为O(n^2)


#include <stdio.h>
#include <algorithm>

#define SIZE 1000000+100

using namespace std;

int n, m;

int a[SIZE], b[SIZE], c[SIZE*2];

int main(){
	#ifdef ONLINE_JUDGE
	#else
		freopen("E:\\in.txt", "r", stdin);
	#endif

	scanf("%d", &n);
	int i;
	for(i=0; i<n; i++)
	{
		scanf("%d", &a[i]);
	}

	scanf("%d", &m);
	for(i=0; i<m; i++)
	{
		scanf("%d", &b[i]);
	}

	merge(a, a+n, b, b+m, c);

	printf("%d\n", c[(n+m-1)/2]);
	return 0;
}

inplace_merge

// 还要开辟一个数组？这么麻烦，看我的吧！
#include <stdio.h>
#include <vector>
#include <algorithm>

using namespace std;

int n,m;
vector<int> a;

int main(){
	#ifdef ONLINE_JUDGE
	#else
		freopen("E:\\in.txt", "r", stdin);
	#endif

	scanf("%d", &n);
	int i, t;
	for(i=0; i<n; i++)
	{
		scanf("%d", &t);
		a.push_back(t);
	}
	scanf("%d", &m);
	for(; i<n+m; i++)
	{
		scanf("%d", &t);
		a.push_back(t);
	}
	inplace_merge(a.begin(), a.begin()+n, a.end());// Hi! 我在这
	printf("%d\n", a[(a.size()-1)/2]);
	return 0;
}