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cp-templates/number/basis.cc

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;
}