Submission #270478

#	Time	Username	Problem	Language	Result	Execution time	Memory
270478		egekabas	XOR Sum (info1cup17_xorsum)	C++14	45 / 100	436 ms	16488 KiB

xorsum

#include <bits/stdc++.h>
#define aint(x) (x).begin(), (x).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ld, ld> pld;
int n, a[1000009];
vector<pii> old, cur;
int 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;
    old.resize(n);
    for(int i = 0; i < n; ++i)
        cin >> old[i].ff;
    for(int bit = 0; bit < 32; ++bit){
        for(auto u : old)
            if((u.ff&(1<<bit)) == 0)
                cur.pb(u);
        
        for(auto u : old)
            if((u.ff&(1<<bit)))
                cur.pb({u.ff, u.ss+(1<<bit)});
        
    
        int i1, i2, i3;
        i1 = i2 = i3 = n-1;
        int cnt = 0;
        for(int i = 0; i < n; ++i){
            i1 = max(i1, i-1);
            i2 = max(i2, i-1);
            i3 = max(i3, i-1);
            
            while(i1 >= i && cur[i].ss+cur[i1].ss >= (1<<bit))
                --i1;
            while(i2 >= i && cur[i].ss+cur[i2].ss >= (1<<(bit+1)))
                --i2;
            while(i3 >= i && cur[i].ss+cur[i3].ss >= (1<<(bit+1))+(1<<bit))
                --i3;
            
            cnt += i2-i1+n-1-i3;
        }
        if(cnt%2)
            ans += (1<<bit);
        swap(old, cur);
        cur.clear();
    }
    cout << ans << '\n';
}

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