Submission #270467

#	Time	Username	Problem	Language	Result	Execution time	Memory
270467		egekabas	XOR Sum (info1cup17_xorsum)	C++14	45 / 100	452 ms	131076 KiB

xorsum

#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pull;
typedef pair<int, int> pii;
typedef pair<ld, ld> pld;
ll n, a[1000009];
vector<pii> v[32];
ll ans = 0;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);

    cin >> n;
    for(ll i = 0; i < n; ++i)
        cin >> a[i];
    for(ll bit = 0; bit < 32; ++bit){
        if(bit == 0){
            for(ll i = 0; i < n; ++i)
                if(a[i]%2 == 0)
                    v[0].pb({a[i], 0});
            for(ll i = 0; i < n; ++i)
                if(a[i]%2)
                    v[0].pb({a[i], 1});
        }
        else{
            for(auto u : v[bit-1])
                if((u.ff&(1<<bit)) == 0)
                    v[bit].pb(u);
            for(auto u : v[bit-1])
                if((u.ff&(1<<bit)))
                    v[bit].pb({u.ff, u.ss+(1LL<<bit)});
        }
        ll i1, i2, i3;
        i1 = i2 = i3 = n-1;
        ll cnt = 0;
        for(ll i = 0; i < n; ++i){
            i1 = max(i1, i-1);
            i2 = max(i2, i-1);
            i3 = max(i3, i-1);
            
            while(i1 >= i && v[bit][i].ss+v[bit][i1].ss >= (1LL<<bit))
                --i1;
            while(i2 >= i && v[bit][i].ss+v[bit][i2].ss >= (1LL<<(bit+1)))
                --i2;
            while(i3 >= i && v[bit][i].ss+v[bit][i3].ss >= (1LL<<(bit+1))+(1LL<<bit))
                --i3;
            
            cnt += i2-i1+n-1-i3;
        }
        if(cnt%2)
            ans += (1LL<<bit);
    }
    cout << ans << '\n';
}

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