Submission #763884

#	Time	Username	Problem	Language	Result	Execution time	Memory
763884		Trunkty	XOR Sum (info1cup17_xorsum)	C++14	100 / 100	1061 ms	49380 KiB

xorsum

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

int n,ans;
int arr[1000005];
vector<int> va;

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> arr[i];
        va.push_back(arr[i]);
    }
    for(int j=0;j<=31;j++){
        int curr=0;
        vector<int> v;
        for(int i:va){
            v.push_back(i%(1LL<<j));
        }
        int cnt=0;
        for(int i:v){
            if(i+i>=(1LL<<j) and i+i<(1LL<<(j+1LL))){
                cnt++;
            }
        }
        int pa=n,pb=n;
        for(int i:v){
            while(pa!=0 and i+v[pa-1]>=(1LL<<j)){
                pa--;
            }
            while(pb!=0 and i+v[pb-1]>=(1LL<<(j+1LL))){
                pb--;
            }
            cnt += pb-pa;
        }
        curr += cnt/2LL;
        vector<int> va2;
        for(int i:va){
            if(i&(1LL<<j)){
                curr += (n+1);
            }
            else{
                va2.push_back(i);
            }
        }
        for(int i:va){
            if(i&(1LL<<j)){
                va2.push_back(i);
            }
        }
        va = va2;
        if(curr%2){
            ans += (1LL<<j);
        }
    }
    cout << ans << "\n";
    return 0;
}

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