vl ntt_rev(vl& a) {
vl res = ntt(a);
ll in = inv(a.size());
F0R(i,sz(res)) res[i] = res[i]*in % mod;
reverse(res.begin() + 1, res.end());
return res;
}
int lis(const vl& in, vi& liss, vi& parents) {
// position j gives index of the last element in "best"
// known lis of length j (where best means ends in
// smallest element)
vi length_idx(in.size() + 1, -1);
// position i gives the immediate predecessor of element i
// in best known lis
parents.resize(in.size(), -1);
// gives the length of the best known lis ending in pos i
liss.resize(in.size(), -1);
// best known length
int L = 0;
for(int i = 0; i < in.size(); ++i) {
// binary search for largest pos j <= L s.t.
// in[length_idx[j]] < in[i]
// i.e. the lis we can append in[i] onto
int low = 1, high = L;
while(low <= high) {
int mid = ceil((low+high)/2);
if(in[length_idx[mid]] < in[i])
low = mid+1;
else
high = mid-1;
}
// low is length of lis ending in in[i]
parents[i] = length_idx[low-1];
length_idx[low] = i;
liss[i] = low;
// update best known length
L = max(L, low);
}
return L;
}
void unionEquals(vl & G, DisjointSet &ds, CmpByMask cmp)
{
for (uint i = 0; i < G.size() - 1; ++i)
{
/* if previous less than next */
if (cmp(G[i], G[i + 1]))
{
continue;
}
/* two adjacent nodes are equal */
/* check if they belong to different component and union them */
/* BUG: keep index in G */
if (ds.findSet(i) != ds.findSet(i + 1))
{
ds.unionNodes(i, i + 1);
}
}
}
