/* Problem URL: https://codeforces.com/edu/course/2/lesson/7/3/practice/contest/289392/problem/C */ #include #include #include using namespace std; using namespace __gnu_pbds; template > using ordered_set = tree; #define V vector #define rmin(a, b) a = min(a, b) #define rmax(a, b) a = max(a, b) #define rep(i, lim) for (int i = 0; i < (lim); i++) #define nrep(i, s, lim) for (int i = s; i < (lim); i++) #define repv(i, v) for (auto &i : (v)) #define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; } #define sortv(v) sort(v.begin(), v.end()) #define all(v) (v).begin(), (v).end() using vi = vector; using vvi = vector; using vvvi = vector; using vvvvi = vector; using ll = long long; using vl = vector; using vvl = vector; using vvvl = vector; using vvvvl = vector; template auto operator<<(ostream &os, const vector &vec)->ostream& { os << vec[0]; for (size_t i = 1; i < vec.size(); i++) { os << ' ' << vec[i]; } os << '\n'; return os; } template auto operator>>(istream &is, vector &vec)->istream& { for (auto &i : vec) { is >> i; } return is; } template auto operator<<(ostream &os, const vector> &vec)->ostream& { for (auto &i : vec) { os << i[0]; for (size_t j = 1; j < i.size(); j++) { os << ' ' << i[j]; } os << '\n'; } return os; } template auto operator>>(istream &is, vector> &vec)->istream& { for (auto &i : vec) { for (auto &j : i) { is >> j; } } return is; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, m; cin >> n >> m; struct query { int type; int l; int r; int u; int v; int i; }; V queries; vi ans; map, int> prev; int time = 0; rep(i, m) { char op; cin >> op; if (op == '?') { queries.emplace_back(1, time, time, 0, 0, ans.size()); ans.emplace_back(); continue; } int a, b; cin >> a >> b; a--, b--; if (a > b) { swap(a, b); } if (op == '-') { queries[prev[{a, b}]].r = time; time++; continue; } time++; prev[{a, b}] = queries.size(); queries.emplace_back(0, time, INT32_MAX >> 1, a, b, -1); } vi dsu(n); vi size(n); stack> rev; int c; auto init = [&]() { c = n; rep(i, n) { dsu[i] = i; size[i] = 1; } }; init(); function find_p = [&](int i) { if (dsu[i] == i) { return i; } return find_p(dsu[i]); }; auto join = [&](int a, int b) { a = find_p(a); b = find_p(b); if (a == b) { return; } c--; if (size[a] < size[b]) { swap(a, b); } if (size[a] == size[b]) { size[a]++; } dsu[b] = a; rev.emplace(a, b); }; auto save = [&]() { rev.emplace(-1, -1); }; auto rollback = [&]() { while (rev.top().first != -1) { auto [a, b] = rev.top(); rev.pop(); if (size[b] == size[a] - 1) { size[a]--; } dsu[b] = b; c++; } rev.pop(); }; function&)> func = [&](int l, int r, V &queries) { if (l == r) { save(); repv(i, queries) { if (i.type == 0 && l >= i.l && r <= i.r) { join(i.u, i.v); } } repv(i, queries) { if (i.type == 1 && i.l == l) { ans[i.i] = c; } } rollback(); return; } V queries2; save(); repv(i, queries) { if (l >= i.l && r <= i.r) { join(i.u, i.v); continue; } if (l <= i.r && i.l <= r) { queries2.emplace_back(i); } } int mid = (l + r) >> 1; func(l, mid, queries2); func(mid + 1, r, queries2); rollback(); }; func(0, time, queries); repv(i, ans) { cout << i << '\n'; } }