Submission #1313962

#	Time	Username	Problem	Language	Result	Execution time	Memory
1313962		ulvix	XOR Sum (info1cup17_xorsum)	C++20	56 / 100	1641 ms	8180 KiB

xorsum

#include <bits/stdc++.h>
#ifdef ULVI
    #include "debug.hpp"
#else
    #define db(...)
    #define dbv(v)
    #define line()
#endif
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define ff first
#define ss second
#define enld endl
using namespace std;
using namespace __gnu_pbds;
typedef int ll;
typedef pair<ll,ll> pll;
const ll sz=2e5+100;
const ll lg=30;
const ll mod=1e9+7;
const ll inf=1e18;
template<class T>
using indexed_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

void solve(){
    ll n;
    cin>>n;
    vector<ll> v(n);
    for(ll i=0;i<n;i++) cin>>v[i];
    ll ans=0;
    for(ll b=0;b<lg;b++){
        ll pw=(1ll<<b);
        ll d=(pw+1)/2;
        vector<ll> a(n);
        ll cnt=0,cnt1=0;
        for(ll i=0;i<n;i++){
            a[i]=v[i]&(pw-1);
            if(v[i]>>b&1) cnt1++;
            if(a[i]>=d) cnt++;
        }
        ll cnt0=n-cnt1,pt=0;
        sort(all(a));
        for(ll i=n-1;i>=1;i--){
            while(pt<i && a[pt]<pw-a[i]) pt++;
            if(pt<i) cnt=(cnt+i-pt)%2;
            else break;
        }
        cnt1%=2;
        cnt0%=2;
        cnt=(cnt+cnt0*cnt1)%2;
        if(cnt) ans+=pw;
    }
    cout<<ans<<'\n';
}

int main(){
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    ll t=1;
    // cin>>t;
    for(ll _=1;_<=t;_++){
        // cout<<"Scenario #"<<_<<":\n";
        solve();
    }
}

Compilation message (stderr)

xorsum.cpp:25:14: warning: overflow in conversion from 'double' to 'll' {aka 'int'} changes value from '1.0e+18' to '2147483647' [-Woverflow]
   25 | const ll inf=1e18;
      |              ^~~~

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