#include #include #include #include template class PalindromicTree { struct Node { std::string val; const int suffix_link; std::array ch; const int len; const int suffix_link_depth;// the number of palindromic suffixes int cnt; Node(int suffix_link, int len, int depth) : suffix_link(suffix_link), ch(), len(len), suffix_link_depth(depth), cnt(1) { std::fill(ch.begin(), ch.end(), -1); }; void dump(){ std::cerr << "val : " << val << "\n"; std::cerr << "cnt : " << cnt << "\n"; std::cerr << "suffix_link : " << suffix_link << "\n"; std::cerr << "suffix_link_depth : " << suffix_link_depth << "\n"; for(int j = 0; j < alphabetSize; ++j){ if(ch[j] >= 0){ std::cout << std::string(1,'a'+j) << " " << ch[j] << std::endl; } } std::cerr << "\n"; } }; public: std::vector nodes; std::vector dat; int len; std::vector A; PalindromicTree() : nodes({Node(-1,-1,0), Node(0,0,1)}), dat(), len(0), A() {} bool push_back(T c){ dat.emplace_back(c); ++len; int parent_idx = A.empty() ? 0 : A.back(); // std::cerr << parent_idx << " " << len-2-nodes[parent_idx].len << std::endl; while(len-2-nodes[parent_idx].len < 0 or dat[len-2-nodes[parent_idx].len] != c){ parent_idx = nodes[parent_idx].suffix_link; } int v_idx = nodes[parent_idx].ch[c-min_element]; if(v_idx != -1){ ++nodes[v_idx].cnt; A.emplace_back(v_idx); return false; } int suffix_link = nodes[parent_idx].suffix_link; while(suffix_link >= 0 and (len-2-nodes[suffix_link].len < 0 or dat[len-2-nodes[suffix_link].len] != c)){ suffix_link = nodes[suffix_link].suffix_link; } if(suffix_link >= 0 and len-2-nodes[suffix_link].len >= 0 and dat[len-2-nodes[suffix_link].len] == c){ assert(nodes[suffix_link].ch[c-min_element] >= 0); suffix_link = nodes[suffix_link].ch[c-min_element]; } if(suffix_link < 0) suffix_link = 1; v_idx = nodes.size(); nodes[parent_idx].ch[c-min_element] = v_idx; nodes.emplace_back(suffix_link,nodes[parent_idx].len+2,nodes[parent_idx].suffix_link_depth+1); if(nodes[v_idx].len == 1) nodes[v_idx].val = c; else nodes[v_idx].val = c + nodes[parent_idx].val + c; A.emplace_back(v_idx); return true; } size_t num_unique_palindrome() const noexcept { return nodes.size()-2; } }; #include using namespace std; void solve(){ string s, t; cin >> s >> t; const int alphabet_size = 26; PalindromicTree S, T; for(auto c : s) S.push_back(c); for(auto c : t) T.push_back(c); for(int i = S.nodes.size()-1; i >= 0; --i){ int sl = S.nodes[i].suffix_link; if(sl < 0) continue; S.nodes[sl].cnt += S.nodes[i].cnt; } for(int i = T.nodes.size()-1; i >= 0; --i){ int sl = T.nodes[i].suffix_link; if(sl < 0) continue; T.nodes[sl].cnt += T.nodes[i].cnt; } string tmp; auto solve = [&](auto& solve, int vs, int vt) -> long long { long long ret = 0; if(S.nodes[vs].len > 0){ long long cnt = S.nodes[vs].cnt*T.nodes[vt].cnt; ret += cnt; } for(int i = 0; i < alphabet_size; ++i){ int us = S.nodes[vs].ch[i], ut = T.nodes[vt].ch[i]; if(us < 0 or ut < 0) continue; tmp.push_back('A'+i); ret += solve(solve,us,ut); tmp.pop_back(); } return ret; }; long long ans = solve(solve,0,0) + solve(solve,1,1); cout << ans << endl; } void debug(){ string s; cin >> s; const int alphabet_size = 26; PalindromicTree eerTree; for(auto c : s){ eerTree.push_back(c); } for(size_t i = 0; i < eerTree.nodes.size(); ++i){ cerr << "Node " << i << "\n"; eerTree.nodes[i].dump(); } cout << eerTree.num_unique_palindrome() << endl; } int main(){ solve(); // debug(); }