#include <bits/stdc++.h>
using namespace std;
template<typename TH>
void _dbg(const char* sdbg, TH h)
{
cerr << sdbg << " = " << h << "\n";
}
template<typename TH, typename... TA>
void _dbg(const char* sdbg, TH h, TA... t)
{
while (*sdbg != ',') cerr << *sdbg++;
cerr << " = " << h << ",";
_dbg(sdbg + 1, t...);
}
#define db(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
#define chkpt cerr << "--- Checkpoint here ---\n";
const int N=1e6+6;
int n;
int64_t a[N];
void Sub1(){
int ans=0;
for(int i=1;i<=n;++i){
for(int j=i;j<=n;++j){
ans^=(a[i]+a[j]);
}
}
cout<<ans<<'\n';
}
int Check(int pos){
int res=0;
vector<vector<int>> vec(2);
for(int i=1;i<=n;++i){
int64_t val=0;
for(int j=0;j<pos;++j){
if((a[i]>>j)&1){
val|=1<<j;
}
}
vec[(a[i]>>pos)&1].push_back(val);
}
for(int i=0;i<2;++i){
sort(begin(vec[i]),end(vec[i]));
}
for(int i=0;i<vec[0].size();++i){
int64_t val=(1<<pos)-vec[0][i];
int lo=0,hi=i,pos=-1;
while(lo<=hi){
int mi=(lo+hi)/2;
if(vec[0][mi]>=val){
pos=mi;
hi=mi-1;
}
else{
lo=mi+1;
}
}
if(~pos){
res^=((i-pos+1)%2);
}
}
for(int i=0;i<vec[1].size();++i){
int64_t val=(1<<pos)-vec[1][i];
int lo=0,hi=i,pos=-1;
while(lo<=hi){
int mi=(lo+hi)/2;
if(vec[1][mi]>=val){
pos=mi;
hi=mi-1;
}
else{
lo=mi+1;
}
}
if(~pos){
res^=((i-pos+1)%2);
}
}
for(int i=0;i<vec[0].size();++i){
int64_t val=(1<<pos)-vec[0][i];
int lo=0,hi=(int)vec[1].size()-1,pos=-1;
while(lo<=hi){
int mi=(lo+hi)/2;
if(vec[1][mi]<val){
pos=mi;
lo=mi+1;
}
else{
hi=mi-1;
}
}
if(~pos){
res^=((pos+1)%2);
}
}
return res;
}
void Sub2(){
// db(Check(1));
int64_t ans=0;
for(int i=0;i<=21;++i){
if(Check(i)){
ans+=(int64_t)1<<i;
}
}
cout<<ans;
}
void Gen(){
srand(time(0));
freopen("info1cup17_xorsum.inp","w",stdout);
int n=rand()%5+1;
cout<<n<<'\n';
for(int i=1;i<=n;++i){
cout<<rand()%10+1<<' ';
}
exit(0);
}
int main()
{
// Gen();
// freopen("info1cup17_xorsum.inp","r",stdin);
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n;
for(int i=1;i<=n;++i){
cin>>a[i];
}
// Sub1();
Sub2();
return 0;
}
Compilation message
xorsum.cpp: In function 'int Check(int)':
xorsum.cpp:52:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<vec[0].size();++i){
~^~~~~~~~~~~~~~
xorsum.cpp:69:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<vec[1].size();++i){
~^~~~~~~~~~~~~~
xorsum.cpp:86:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0;i<vec[0].size();++i){
~^~~~~~~~~~~~~~
xorsum.cpp: In function 'void Gen()':
xorsum.cpp:119:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
freopen("info1cup17_xorsum.inp","w",stdout);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
19 ms |
512 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1700 ms |
16108 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1700 ms |
16108 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
19 ms |
512 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
19 ms |
512 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
