Submission #690977

#	Time	Username	Problem	Language	Result	Execution time	Memory
690977		Ahmed_Solyman	XOR Sum (info1cup17_xorsum)	C++14	18 / 100	1688 ms	36448 KiB

xorsum

#include <bits/stdc++.h>
#include <ext/rope>
 
using namespace std;
using namespace __gnu_cxx;
#pragma GCC optimize("-Ofast")
#pragma GCC optimize("-O1")
//-------------------------------------------------------------//
typedef long long ll;
typedef unsigned long long ull;
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define PI acos(-1)
#define lb lower_bound
#define ub upper_bound
#define endl '\n'
#define all(v) v.begin(),v.end()
#define allr(v) v.rbegin(),v.rend()
#define sum_to(n) (n*(n+1))/2
#define pb push_back
#define pf push_front
#define sz size()
#define fil(arr,x) memset(arr,x,sizeof(arr))
const ll mod=1e9+7;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,-1,1};
//-------------------------------------------------------------//
ll lcm(ll a,ll b)
{
    return (max(a,b)/__gcd(a,b))*min(a,b);
}
void person_bool(bool x)
{
    cout<<(x?"YES":"NO")<<endl;
}
int main()
{
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    fast
    int n;cin>>n;
    vector<int>arr(n);
    for(auto &i:arr)cin>>i;
    int ans=0;
    map<int,int>fr;
    for(int i=0;i<n;i++){
    	++fr[arr[i]];
    }
    for(auto i:fr){
    	for(auto j:fr){
    		if(i.first==j.first){
    			ll k=(i.second*(i.second+1)/2);
    			if(k&1){
	    			ans^=i.first*2;
	    		}
    			continue;
    		}
    		ll k=i.second*j.second;
    		if(k&1){
    			ans^=i.first+j.first;
    		}
    	}
    	fr[i.first]=0;
    }
    cout<<ans<<endl;
    return 0;
}

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