#include <bits/stdc++.h>
#include <ostream>
#define pb push_back
#define s second
#define f first
#define pb push_back
#define pii pair <int,int>
#define ll long long
#define left h*2,l,(l + r)/2
#define right h*2+1,(l + r)/2 + 1,r
#define int ll
using namespace std;
const int N = 1e6 + 5,inf = 1e9;
int a[N],arr[N];
signed main() {
ios_base::sync_with_stdio(0),cin.tie(NULL),cout.tie(NULL);
int n;
cin>>n;
for (int i = 1; i <= n; i++){
cin >> a[i];
}
int ans=0,add=0;
for (int i = 0; i <= 30; i++){
for (int j = 1; j <= n; j++)
arr[j] = (a[j] & ((1<<(i + 1)) - 1));
sort(arr+1,arr+n+1);
vector <pair <pii,int> > v;
for (int j = 1; j <= n; j++){
int sum = (arr[j] + arr[n]);
sum >>= i;
sum &= 3;
if (v.size() && v.back().s == sum) v.back().f.s += 1;
else {
v.pb({{j,j},sum});
}
}
int cnt = 0,add = 0;
for (int j = n; j >= 1; j--){
vector <pair<pii,int> > vnew;
for (int k = 0; k < v.size(); k++){
int l = v[k].f.f,r = v[k].f.s,val = v[k].s;
while (r + 1 <= n){
int sum = (((arr[r + 1] + arr[j]) >> i) & 3);
if (sum == val) r += 1;
else break;
}
while (l <= n){
int sum = (((arr[l] + arr[j]) >> i) & 3);
if (sum != val) l += 1;
else break;
}
if (l <= r){
vnew.pb({{l,r},val});
}
}
sort(vnew.begin(),vnew.end());
int id = 1,k = 0;
vector <pair<pii,int> > vec;
while (k < vnew.size()){
if (id == vnew[k].f.f){
vec.pb(vnew[k]);
id = vnew[k].f.s + 1;
k++;
}else{
int l = id,r = id,val = (((arr[id] + arr[j]) >> i) & 3);
while (r + 1 <= n){
int sum = (((arr[r + 1] + arr[j]) >> i) & 3);
if (sum == val) r += 1;
else break;
}
vec.pb({{l,r},val});
id = r + 1;
}
}
sort(vec.begin(),vec.end());
for (int k = 0; k <vec.size(); k++){
int s = vec[k].s;
if (s == 3 || s == 1){
int l = vec[k].f.f,r = vec[k].f.s;
l = max(l,j);
cnt += max(0LL,(r - l + 1));
}
}
int s = (((arr[j]*2) >> i) & 3);
v = vec;
}
if (cnt & 1) ans |= (1LL<<i);
}
cout<<ans;
}
Compilation message
xorsum.cpp: In function 'int main()':
xorsum.cpp:50:25: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<std::pair<long long int, long long int>, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
50 | for (int k = 0; k < v.size(); k++){
| ~~^~~~~~~~~~
xorsum.cpp:73:16: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<std::pair<long long int, long long int>, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
73 | while (k < vnew.size()){
| ~~^~~~~~~~~~~~~
xorsum.cpp:92:25: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<std::pair<long long int, long long int>, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
92 | for (int k = 0; k <vec.size(); k++){
| ~~^~~~~~~~~~~
xorsum.cpp:4:11: warning: unused variable 'second' [-Wunused-variable]
4 | #define s second
| ^~~~~~
xorsum.cpp:101:11: note: in expansion of macro 's'
101 | int s = (((arr[j]*2) >> i) & 3);
| ^
xorsum.cpp:46:17: warning: unused variable 'add' [-Wunused-variable]
46 | int cnt = 0,add = 0;
| ^~~
xorsum.cpp:27:13: warning: unused variable 'add' [-Wunused-variable]
27 | int ans=0,add=0;
| ^~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
30 ms |
2392 KB |
Output is correct |
2 |
Correct |
23 ms |
2396 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1665 ms |
20560 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Execution timed out |
1665 ms |
20560 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
30 ms |
2392 KB |
Output is correct |
2 |
Correct |
23 ms |
2396 KB |
Output is correct |
3 |
Correct |
586 ms |
7512 KB |
Output is correct |
4 |
Correct |
552 ms |
7708 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
30 ms |
2392 KB |
Output is correct |
2 |
Correct |
23 ms |
2396 KB |
Output is correct |
3 |
Execution timed out |
1665 ms |
20560 KB |
Time limit exceeded |
4 |
Halted |
0 ms |
0 KB |
- |