poj 2388 Who's in the Middle

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define Max_N 100002
int heap[Max_N],sz;
void push(int x){
	int i=sz++;
	while(i>0){
		int p=(i-1)>>1;
		if(heap[p]<=x) break;
		heap[i]=heap[p];
		i=p;
	}
	heap[i]=x;
}
int pop(){
	int x,i=0,ret=heap[0];
	x=heap[--sz];
	while((i<<1)+1<sz){
		int a=(i<<1)+1,b=(i<<1)+2;
		if(b<sz && heap[a]>heap[b]) a=b;
		if(heap[a]>=x) break;
		heap[i]=heap[a];
		i=a;
	}
	heap[i]=x;
	return ret;
}
int main()
{
	int i,n,ret;
	while(EOF!=scanf("%d",&n)){
		sz=0;
		for(i=0;i<n;i++){
			scanf("%d",&ret);
			push(ret);
		}
		for(i=0; i < n>>1;i++) pop();
		printf("%d\n",pop());
	}
	return 0;
}