Submission #691020

#	Time	Username	Problem	Language	Result	Execution time	Memory
691020		Ahmed_Solyman	XOR Sum (info1cup17_xorsum)	C++14	18 / 100	1686 ms	58440 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]];
    }
    vector<int>v;
    set<int>s;
    map<int,int>vis;
    for(int i=0;i<n;i++){
    	if(fr[arr[i]]&1)s.insert(arr[i]);
    	if(vis[arr[i]])continue;
    	vis[arr[i]]=1;
    	ll k=(fr[arr[i]]*(fr[arr[i]]+1))/2;
    	if(k&1)ans^=(arr[i]*2);
    }
    for(auto i:s)v.pb(i);
    for(int i=0;i<v.sz;i++){
    	for(int j=i+1;j<v.sz;j++){
    		ans^=(v[i]+v[j]);
    	}
    }
    cout<<ans<<endl;
    return 0;
}

Compilation message (stderr)

xorsum.cpp: In function 'int main()':
xorsum.cpp:59:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     for(int i=0;i<v.sz;i++){
      |                  ^
xorsum.cpp:60:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |      for(int j=i+1;j<v.sz;j++){
      |                     ^

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