Submission #763875

#	Time	Username	Problem	Language	Result	Execution time	Memory
763875		Trunkty	XOR Sum (info1cup17_xorsum)	C++14	45 / 100	1672 ms	28876 KiB

xorsum

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll

int n,ans;
int arr[1000005];

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> arr[i];
    }
    for(int j=0;j<=40;j++){
        int curr=0;
        vector<int> v;
        for(int i=1;i<=n;i++){
            if(arr[i]&(1LL<<j)){
                curr += (n+1);
            }
            v.push_back(arr[i]%(1LL<<j));
        }
        sort(v.begin(),v.end());
        int cnt=0;
        for(int i:v){
            if(i+i>=(1LL<<j) and i+i<(1LL<<(j+1LL))){
                cnt++;
            }
            int low=0,high=v.size();
            while(low!=high){
                int mid = (low+high)/2;
                if(i+v[mid]>=(1LL<<j)){
                    high = mid;
                }
                else{
                    low = mid+1;
                }
            }
            int low2=0,high2=v.size();
            while(low2!=high2){
                int mid2 = (low2+high2)/2;
                if(i+v[mid2]>=(1LL<<(j+1LL))){
                    high2 = mid2;
                }
                else{
                    low2 = mid2+1;
                }
            }
            cnt += low2-low;
        }
        curr += cnt/2LL;
        if(curr%2){
            ans += (1LL<<j);
        }
    }
    cout << ans << "\n";
    return 0;
}

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