Submission #1149477

#	Time	Username	Problem	Language	Result	Execution time	Memory
1149477		KluydQ	XOR Sum (info1cup17_xorsum)	C++20	56 / 100	1695 ms	8276 KiB

xorsum

#include <bits/stdc++.h>
 
#define respagold ios_base::sync_with_stdio(0), cin.tie(0);
#define ll long long
#define int2 __int128_t
#define FOR( i, x, n, d ) for( int i = x; i <= n; i += d )
#define FORR( i, x, n, d ) for( int i = x; i >= n; i -= d )
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x.size())
#define pb push_back
#define ins insert
#define lb lower_bound
#define ub upper_bound
#define pii pair <int, int>
#define mkp make_pair
 
using namespace std;
 
const int N = 1e6 + 123;
const int inf = 2e18;
const int MOD = 1e9 + 7;
const int MOD1 = 998244353;
const int P = 6547;
 
int a[N], b[N], c[N], n, m, x, y, z, w;
 
mt19937 rng( chrono::steady_clock::now().time_since_epoch().count());
 
int rand( int l, int r )
{
    uniform_int_distribution <int> uid( l, r );
    return uid( rng );
}
void solve()
{
	cin >> n;
	
	FOR( i, 1, n, 1 ) cin >> b[i];
	
	FOR( k, 0, 30, 1 )
	{
		FOR( i, 1, n, 1 ) a[i] = b[i] & (( 1 << (k + 1)) - 1 );
		sort( a + 1, a + n + 1 );
		
		int u1 = n, u2 = n, u3 = n;
		ll ans = 0;
		FOR( i, 1, n, 1 )
		{
		
			while(a[u1] + a[i] >= (1 << k) && u1 > 0 ) u1 --;
			while(a[u2] + a[i] >= (1 << (k + 1)) && u2 > 0 ) u2 --;
			while(a[u3] + a[i] >= (1 << (k + 1)) + (1 << k) && u3 > 0 ) u3 --;
			ans += u2 - u1;
			ans += n - u3;
		}
		FOR(i, 1, n, 1) if((1 << k) & (a[i] * 2)) ans++;
//		for(int i = 1; i <= n; ++ i) cout << a[i] << ' ';
//		cout << '\n';	
//		cout << k << ' '<< ans << '\n';
		ans /= 2;
		
		if( ans % 2 ) x += ( 1 << k );
	}
	
	cout << x;
}
signed main() 
{
//	freopen("connect.in", "r", stdin);
//	freopen("connect.out", "w", stdout);
	    
    respagold
    
    int test = 1;
    
    if( !test ) cin >> test;
	
	while( test -- )
	{
		solve();
	}
}
// solved by KluydQ  

Compilation message (stderr)

xorsum.cpp:22:17: warning: overflow in conversion from 'double' to 'int' changes value from '2.0e+18' to '2147483647' [-Woverflow]
   22 | const int inf = 2e18;
      |                 ^~~~

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