Submission #270505

#	Time	Username	Problem	Language	Result	Execution time	Memory
270505		Atill83	XOR Sum (info1cup17_xorsum)	C++14	0 / 100	1171 ms	67020 KiB

xorsum

#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl '\n'
using namespace std;
const long long INF = (long long) 1e18;
const int mod = (int) 1e9+7;
const int MAXN = (int) 1e6+5;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll n;
int v[MAXN];
pll b[MAXN], nw[MAXN];
int pw[45];
const int L = 29;

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);


    cin>>n;

    for(ll i = 0; i < n; i++){
        cin>>v[i];
        b[i] = {v[i] % 2, i};
    }
    
    sort(b, b + n);
    
    pw[0] = 1;

    for(ll i = 1; i < L; i++){
        pw[i] = pw[i - 1] * 2;
    }

    int ans = 0;

    for(ll i = 0; i < L; i++){
        ll cnt = 0;
        int r3 = n, r2 = n, r1 = n;

        for(int j = 0; j < n; j++){
            while(r3 && b[j].ff + b[r3 - 1].ff >= pw[i] + pw[i + 1]) r3--;
            while(r2 && b[j].ff + b[r2 - 1].ff >= pw[i + 1]) r2--;
            while(r1 && b[j].ff + b[r1 - 1].ff >= pw[i]) r1--;
            cnt += n - r1 - (r3 - r2);
        }

        for(int j = 0; j < n; j++){
            if((2LL*b[j].ff) & pw[i]) cnt++;
        }
        assert(cnt % 2 == 0);
        cnt /= 2;
        if(cnt % 2) ans += pw[i];

        if(i + 1 == L) break;
        int last = 0;
        for(int j = 0; j < n; j++){
            if((v[b[j].ss] & pw[i + 1]) == 0)
                nw[last++] = b[j];
        }

        for(int j = 0; j < n; j++){
            if((v[b[j].ss] & pw[i + 1]) != 0){
                b[j].ff += pw[i + 1];
                nw[last++] = b[j];
            }
        }
        for(int j = 0; j < n; j++){
            b[j] = nw[j];
            nw[j] = {-1, -1};
        }
        assert(last == n);
    }

    cout<<ans<<endl;


    #ifdef Local
        cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
    #endif
}

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