162 lines
3.1 KiB
C++

/* Problem URL: https://codeforces.com/edu/course/2/lesson/7/3/practice/contest/289392/problem/A */
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
#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<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using ll = long long;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;
template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
os << vec[0];
for (size_t i = 1; i < vec.size(); i++) {
os << ' ' << vec[i];
}
os << '\n';
return os;
}
template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
for (auto &i : vec) {
is >> i;
}
return is;
}
template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &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<class v>
auto operator>>(istream &is, vector<vector<v>> &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;
vi dsu(n);
vi size(n);
rep(i, n) {
dsu[i] = i;
size[i] = 1;
}
stack<pair<int, int>> re;
function<int(int)> find_p = [&](int i) {
if (dsu[i] == i) {
return i;
}
return find_p(dsu[i]);
};
int c = n;
auto join = [&](int a, int b) {
a = find_p(a);
b = find_p(b);
if (a == b) {
return;
}
if (size[a] < size[b]) {
swap(a, b);
}
re.emplace(a, b);
dsu[b] = a;
if (size[a] == size[b]) {
size[a]++;
}
c--;
};
auto rollback = [&]() {
while (re.top().first != -1) {
auto [a, b] = re.top();
re.pop();
if (size[b] == size[a] - 1) {
size[a]--;
}
dsu[b] = b;
c++;
}
re.pop();
};
while (m--) {
string op;
cin >> op;
if (op[0] == 'u') {
int a, b;
cin >> a >> b;
join(a - 1, b - 1);
cout << c << '\n';
continue;
}
if (op[0] == 'p') {
re.emplace(-1, -1);
continue;
}
rollback();
cout << c << '\n';
}
}