Submission #4261807

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Source Code Expand

/*
	Name: F-冒泡排序 
	Author: RoseKey
	Date: 14/02/19 16:49
	Description: 模拟+找规律 
*/

#include <set>
#include <map>
#include <stack>
#include <queue>
#include <cmath>
#include <cstdio>
#include <vector>
#include <bitset>
#include <cstring>
#include <utility>
#include <iostream>
#include <algorithm>
#define LL long long
#define Rg register
#define RI register int
#define RC register char
#define ed puts("") 
#define pair pair<LL,LL>
#define space putchar(' ')
using namespace std;
    
template <typename tp> inline void read(tp & x)
{	
    x=0;
    RI f=1;
    RC c=getchar();
    while(c<'0' || c>'9'){if(c=='-') f=-1;c=getchar(); }
    while(c>='0' && c<='9'){x=(x<<1)+(x<<3)+(c^48);c=getchar();} 
 	x*=f;
} 	
    
template <typename Tp> inline void print(Tp x)
{		
    if(x<0) x=-x,putchar('-');
    if(x>9) print(x/10);
    putchar(x%10+'0');
}

int n;
LL ans;
LL b[100005];
struct qwq
{
	int num;
	int val;
	bool flag;
}a[100005];

inline bool cmp(qwq x,qwq y)
{
	return x.val<y.val;
}
//qwq
int main()
{
	read(n);
	for(RI i=1;i<=n;++i)
		read(a[i].val),a[i].num=i;
	stable_sort(a+1,a+n+1,cmp);
	for(RI i=1;i<=n;++i)
	{
		int k=i;
		int kk=a[i].val;
		int h=i%2;
		int hh=a[i].num%2;
		if(h==hh) a[i].flag=1;
		if(a[i].flag) continue;
	}
	for(RI i=1;i<=n;++i)
	{
		if(a[i].flag) continue;
		ans++;
	}
	if(ans==0)
	{
		print(0);
		return 0;
	}
	print(ans/2);
	return 0;
}

Submission Info

Judge Result