#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("-O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define mp make_pair
#define ll long long
#define ld long double
#define pb push_back
#define fast_io ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define fs first
#define sc second
#define getfiles ifstream cin("input.txt"); ofstream cout("output.txt");
#define endl '\n'
#define pii pair<int, int>
const int INF = 2000000005;
const ll BIG_INF = 2000000000000000005;
const int mod = 1000000007;
const int P = 31;
const ld PI = 3.141592653589793238462643;
const double eps = 1e-9;
using namespace std;
using namespace __gnu_pbds;
bool valid(int x, int y, int n, int m) {
return x >= 0 && y >= 0 && x < n && y < m;
}
mt19937 rng(1999999973);
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
const int N = 1000000 + 5;
int order[N], p[2][N], o[2], a[N], n, ans = 0;
inline int readint() {
int x = 0;
char ch = getchar_unlocked();
while (ch < '0' || ch > '9') {
ch = getchar_unlocked();
}
while (ch >= '0' && ch <= '9') {
x = (x << 3) + (x << 1) + ch - '0';
ch = getchar_unlocked();
}
return x;
}
signed main() {
fast_io;
n = readint();
for (int i = 0; i < n; i++) {
a[i] = readint();
order[i] = i;
}
int curmask = 0;
int pointer[2] = {o[0], o[1]}, same = 0, col = 0;
for (int bit = 0; bit < 29; bit++) {
o[0] = o[1] = 0;
for (int i = 0; i < n; i++) {
int v = (a[order[i]]>>bit)&1;
p[v][o[v]] = order[i];
o[v]++;
}
pointer[2] = {o[0], o[1]}, same = 0, col = 0;
for (int i = 0; i < n; i++) {
for (int bt = 0; bt < 2; bt++) {
while(pointer[bt] > 0 && (a[p[bt][pointer[bt] - 1]]&curmask) + (a[order[i]]&curmask) >= (1 << bit))
pointer[bt]--;
if (((a[order[i]]>>bit)&1) != bt)
col += pointer[bt];
else
col += o[bt] - pointer[bt];
}
if (((a[order[i]] + a[order[i]])>>bit)&1)
same++;
col &= 3;
}
col = col + 4 - (same&3);
col >>= 1;
col += same;
ans |= ((col&1) << bit);
int cur = 0;
for (int bt = 0; bt < 2; bt++) {
for (int i = 0; i < o[bt]; i++) {
order[cur] = p[bt][i];
cur++;
}
}
curmask <<= 1;
curmask++;
}
cout << ans;
return 0;
}
/*
2
7 0
*/
Compilation message
xorsum.cpp: In function 'int main()':
xorsum.cpp:75:33: error: cannot convert '<brace-enclosed initializer list>' to 'int' in assignment
pointer[2] = {o[0], o[1]}, same = 0, col = 0;
^
