#include <bits/stdc++.h>
#ifdef local
#define safe cerr<<__PRETTY_FUNCTION__<<" line "<<__LINE__<<" safe\n"
#define pary(a...) danb(#a, a)
#define debug(a...) qqbx(#a, a)
template <typename ...T> void qqbx(const char *s, T ...a) {
int cnt = sizeof...(T);
((std::cerr << "\033[1;32m(" << s << ") = (") , ... , (std::cerr << a << (--cnt ? ", " : ")\033[0m\n")));
}
template <typename T> void danb(const char *s, T L, T R) {
std::cerr << "\033[1;32m[ " << s << " ] = [ ";
for (int f = 0; L != R; ++L)
std::cerr << (f++ ? ", " : "") << *L;
std::cerr << " ]\033[0m\n";
}
#else
#define debug(...) ((void)0)
#define safe ((void)0)
#define pary(...) ((void)0)
#endif // local
#define all(v) begin(v),end(v)
#define pb emplace_back
using namespace std;
using ll = int64_t;
const int maxn = 1000025, LGC = 29;
struct TREE : vector<int> {
int less_equal(int x) {
return upper_bound(all(), x) - begin();
}
int greater(int x) {
return end() - upper_bound(all(), x);
}
int calc(int U) {
if (empty()) return 0;
// return #(a[i] > b[j]) where b[i] = U - a[i]
int ans = 0;
for (int i = size()-1, j = 0; i >= 0; i--) {
while (j < size() && at(j) + at(i) <= U) ++j;
if (j > i)
break;
ans += i - j + 1;
}
return ans;
}
} pre[2];
ll calc(TREE &a, TREE &b, int U) {
if (a.empty() || b.empty()) return 0;
ll ans = 0;
for (int i = a.size()-1, j = 0; i >= 0; i--) {
while (j < b.size() && a[i] + b[j] <= U) ++j;
ans += j;
}
return ans;
}
int a[maxn];
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0);
int n;
cin >> n;
for (int i = 0; i < n; i++)
cin >> a[i];
pre[0].reserve(n);
pre[1].reserve(n);
int ans = 0;
for (int b = 0; b < LGC; b++) {
int U = (1<<b) - 1;
int parity = 0;
pre[0].clear();
pre[1].clear();
sort(a, a+n, [U](int x, int y){ return (x & U) < (y & U); });
/*
for (int i = 0; i < n; i++) {
int d = a[i] >> b & 1;
pre[d].push_back(a[i] & U);
parity += pre[!d].less_equal(~a[i] & U);
parity += pre[d].greater(~a[i] & U);
}
*/
for (int i = 0; i < n; i++)
pre[a[i] >> b & 1].pb(a[i] & U);
parity += pre[0].calc(U);
parity += pre[1].calc(U);
parity += calc(pre[0], pre[1], U);
debug(parity);
parity &= 1;
ans |= parity << b;
}
cout << ans << '\n';
}
Compilation message
xorsum.cpp: In member function 'int TREE::calc(int)':
xorsum.cpp:39:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
39 | while (j < size() && at(j) + at(i) <= U) ++j;
| ~~^~~~~~~~
xorsum.cpp: In function 'll calc(TREE&, TREE&, int)':
xorsum.cpp:51:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
51 | while (j < b.size() && a[i] + b[j] <= U) ++j;
| ~~^~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
332 KB |
Output is correct |
2 |
Correct |
8 ms |
332 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1130 ms |
11024 KB |
Output is correct |
2 |
Correct |
1061 ms |
10344 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1130 ms |
11024 KB |
Output is correct |
2 |
Correct |
1061 ms |
10344 KB |
Output is correct |
3 |
Execution timed out |
1636 ms |
11016 KB |
Time limit exceeded |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
332 KB |
Output is correct |
2 |
Correct |
8 ms |
332 KB |
Output is correct |
3 |
Correct |
200 ms |
1272 KB |
Output is correct |
4 |
Correct |
202 ms |
1264 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
8 ms |
332 KB |
Output is correct |
2 |
Correct |
8 ms |
332 KB |
Output is correct |
3 |
Correct |
1130 ms |
11024 KB |
Output is correct |
4 |
Correct |
1061 ms |
10344 KB |
Output is correct |
5 |
Execution timed out |
1636 ms |
11016 KB |
Time limit exceeded |
6 |
Halted |
0 ms |
0 KB |
- |