Submission #783066

#	Time	Username	Problem	Language	Result	Execution time	Memory
783066		Andrey	XOR Sum (info1cup17_xorsum)	C++14	100 / 100	714 ms	25436 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;

vector<long long> haha(0);
long long n;

bool calc(long long k) {
    vector<long long> idk(n);
    long long br1 = 0,ans = 0,l = 0,r = n-1,p1,p2;
    for(long long i = 0; i < n; i++) {
        if(haha[i]&(1 << k)) {
            br1++;
        }
        idk[i] = haha[i]%(1 << k);
    }
    ans+=(br1*(n-br1))%2;
    while(l < n) {
        if(l > r) {
            r++;
        }
        while(r > l && idk[l]+idk[r-1] >= (1 << k)) {
            r--;
        }
        if(idk[l]+idk[r] >= (1 << k)) {
            ans+=((n-r))%2;
            ans%=2;
        }
        l++;
    }
    p1 = 0;
    p2 = n-br1;
    for(int i = 0; i < n; i++) {
        if(haha[i]&(1 << k)) {
            idk[p2] = haha[i];
            p2++;
        }
        else {
            idk[p1] = haha[i];
            p1++;
        }
    }
    for(int i = 0; i < n; i++) {
        haha[i] = idk[i];
        idk[i]%=(1 << k);
    }
    return ans;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    long long a,ans = 0;
    cin >> n;
    for(long long i = 0; i < n; i++) {
        cin >> a;
        haha.push_back(a);
    }
    for(long long i = 0; i < 30; i++) {
        if(calc(i)) {
            ans+=(1 << i);
        }
    }
    cout << ans;
    return 0;
}

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