Submission #359136

#	Time	Username	Problem	Language	Result	Execution time	Memory
359136		ogibogi2004	XOR Sum (info1cup17_xorsum)	C++14	77 / 100	1674 ms	24488 KiB

xorsum

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const ll MAXN=4e6+6;
const ll logN=31;
ll n,ans;
ll a[MAXN];
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	cin>>n;
	for(ll i=1;i<=n;++i)
	{
		cin>>a[i];
	}
	ll ans=0;
	for(ll j=0;j<logN;++j)
	{
		vector<ll>a1;
		if(j!=0)
		{
			for(ll i=1;i<=n;++i)
			{
				if(!(a[i]&(1<<(j-1))))
				{
					a1.push_back(a[i]);
				}
			}
			for(ll i=1;i<=n;++i)
			{
				if(a[i]&(1<<(j-1)))
				{
					a1.push_back(a[i]);
				}
			}
			for(ll i=0;i<a1.size();i++)a[i+1]=a1[i];
		}
		ll cnt0up=0,cnt1up=0,cnt0down=0,cnt1down=0;
		ll p=n,cnt=0;
		for(ll i=1;i<=n;++i)
		{
			if(a[i]&(1<<j))++cnt1up;
			else ++cnt0up;
		}
		for(ll i=1;i<=n;i++)
		{
			while(p>0&&a[p]%(1<<j)+a[i]%(1<<j)>=(1<<j))
			{
				if(a[p]&(1<<j))cnt1down++,cnt1up--;
				else cnt0down++,cnt0up--;
				p--;
			}
			if(a[i]&(1<<j))
			{
				cnt+=cnt0up+cnt1down;
			}
			else
			{
				cnt+=cnt1up+cnt0down;
			}
			if((2*a[i])&(1<<j))cnt++;
		}
		//cout<<j<<" "<<cnt<<endl;
		if((cnt/2)%2==1)
		{
			ans+=(1<<j);
		}
	}
	cout<<ans<<endl;
return 0;
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:38:16: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |    for(ll i=0;i<a1.size();i++)a[i+1]=a1[i];
      |               ~^~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 11 / 11
• Subtask 3: 21 / 21
• Subtask 4: 38 / 38
• Subtask 5: 0 / 23