23 lines
556 B
C++
23 lines
556 B
C++
|
// in-place modification
|
||
|
|
int basis(vector<ll>& a) {
|
||
|
|
int n = a.size();
|
||
|
|
int has = 0;
|
||
|
|
for (int i = 63; ~i and has < n; --i) {
|
||
|
|
for (int j = has; j < n; ++j) {
|
||
|
|
if (a[j] & (ll(1) << i)) {
|
||
|
|
swap(a[j], a[has]);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if (not (a[has] & (ll(1) << i))) continue;
|
||
|
|
for (int j = 0; j < n; ++j) {
|
||
|
|
if (j == has) continue;
|
||
|
|
if (a[j] & (ll(1) << i)) {
|
||
|
|
a[j] ^= a[has];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
++has;
|
||
|
|
}
|
||
|
|
return has;
|
||
|
|
}
|