Submission #74691921

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Source Code Expand

#include<bits/stdc++.h>
#define int long long
//#define MSOD
//#define READ_IN_FILE
#define endl '\n'
#define FAST ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
const int N=2e5+10,P=998244353,MOD=1e9+7,inf=0x3f3f3f3f;
bool cmpbig(int i,int j)
{
	return i>j;
}
double mylog(int x,int y)
{
	return log(x)/log(y);
}
long long qpow(long long a,long long b,long long mod=LLONG_MAX)
{
	long long num=1;
	while(b)
	{
		if(b&1)num=num*a%mod;
		a=a*a%mod;
		b>>=1;
	}
	return num;
}
int n,k,a[N],c[N],ans,num;
int lowbit(int x)
{
	return x&(-x);
}
void update(int x,int k)
{
	while(x<=n)
	{
		c[x]+=k;
		x+=lowbit(x);
	}
}
int query(int l,int r)
{
	int ls=0,rs=0;
	l--;
	while(r>=1)
	{
		rs+=c[r];
		r-=lowbit(r);
	}
	while(l>=1)
	{
		ls+=c[l];
		l-=lowbit(l);
	}
	return rs-ls;
}
void solve()
{
	cin>>n>>k;
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int l=1,r=1;r<=n;)
	{
		while(num<=k&&r<=n)
		{
			update(a[r],1);
			num+=query(a[r]+1,n);
			if(num==k)ans++;
			r++;
		// cout<<l<<' '<<r<<' '<<num<<' '<<ans<<'\n';
		}
		while(num>=k&&l<=r)
		{
			update(a[l],-1);
			num-=query(1,a[l]-1);
			l++;
			if(num==k)ans++;
		// cout<<l<<' '<<r<<' '<<num<<' '<<ans<<'\n';
		}
	}
	cout<<ans;
	return;
}
signed main()
{
	FAST
#ifdef READ_IN_FILE
	freopen(".in","r",stdin);
	freopen(".out","w",stdout);
#endif
	int _T_=1;
#ifdef MSOD
	cin>>_T_;
#endif
	while(_T_--)solve();
	return 0;
}

Submission Info

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