Submission #375327

#	Time	Username	Problem	Language	Result	Execution time	Memory
375327		mode149256	Monthly railway pass (LMIO18_menesinis_bilietas)	C++17	100 / 100	564 ms	116848 KiB

menesinis_bilietas

/*input
5 5
3 1 A
3 5 A
4 5 T
2 3 T
2 1 A
*/
#include <bits/stdc++.h>
using namespace std;

namespace my_template {
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;

typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef vector<pi> vpi;
typedef vector<vpi> vpii;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
typedef vector<pd> vpd;
typedef vector<bool> vb;
typedef vector<vb> vbb;
typedef std::string str;
typedef std::vector<str> vs;

#define x first
#define y second
#define debug(...) cout<<"["<<#__VA_ARGS__<<": "<<__VA_ARGS__<<"]\n"

const ld PI = 3.14159265358979323846264338327950288419716939937510582097494L;

template<typename T>
pair<T, T> operator+(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x + b.x, a.y + b.y); }
template<typename T>
pair<T, T> operator-(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x - b.x, a.y - b.y); }
template<typename T>
T operator*(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.x + a.y * b.y); }
template<typename T>
T operator^(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.y - a.y * b.x); }

template<typename T>
void print(vector<T> vec, string name = "") {
	cout << name;
	for (auto u : vec)
		cout << u << ' ';
	cout << '\n';
}
}
using namespace my_template;

const int MOD = 1000000007;
const ll INF = std::numeric_limits<ll>::max();
const int MX = 500101;

vii trauk(MX);
vpi autob;
vector<unordered_set<int>> newEdges(MX);
vi sz;
vi p;

int findSet(int i) { return (p[i] == i) ? i : (p[i] = findSet(p[i])); }
bool isSameSet(int i, int j) { return findSet(i) == findSet(j); }
void unionSet(int i, int j) {
	if (isSameSet(i, j)) return;

	int x = findSet(i), y = findSet(j);

	if (sz[x] < sz[y]) swap(x, y);
	p[y] = x;
	sz[x] += sz[y];
}

vi visited;
void dfs(int x) {
	visited[x] = true;
	for (auto u : trauk[x]) {
		if (!visited[u]) {
			dfs(u);
			unionSet(x, u);
		}
	}
}

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// #ifndef LOCAL
// 	freopen("lmio_2018_3e2_menesinis_bilietas_vyr.in", "r", stdin);
// 	freopen("lmio_2018_3e2_menesinis_bilietas_vyr.out", "w", stdout);
// #endif
	int N, M;
	cin >> N >> M;
	p = vi(N + 1); for (int i = 0; i <= N; i++) p[i] = i;
	sz = vi(N + 1, 1);
	for (int i = 0; i < M; ++i)
	{
		int a, b;
		char ch;
		cin >> a >> b >> ch; a--; b--;
		if (ch == 'A') {
			autob.emplace_back(a, b);
		} else {
			trauk[a].emplace_back(b);
			trauk[b].emplace_back(a);
		}
	}

	visited = vi(MX, 0);
	for (int i = 0; i < N; ++i)
	{
		if (!visited[i])
			dfs(i);
	}

	for (auto u : autob) {
		if (isSameSet(u.x, u.y)) continue;
		newEdges[findSet(u.x)].insert(findSet(u.y));
		newEdges[findSet(u.y)].insert(findSet(u.x));
	}

	vi allNewNodes;

	{
		set<int> turiu;
		for (int i = 0; i < N; ++i)
		{
			turiu.insert(findSet(i));
		}
		allNewNodes = vi(turiu.begin(), turiu.end());
	}
	int newNodeCnt = (int)allNewNodes.size();

	int ats = 0;
	for (auto u : allNewNodes) {
		// printf("u = %d, newEdges = %d, newNodeCnt = %d\n", u, (int)newEdges[u].size(), newNodeCnt);
		if (1 + (int)newEdges[u].size() == newNodeCnt)
			ats += sz[u];
	}
	printf("%d\n", ats);
}

/* Look for:
* special cases (n=1?)
* overflow (ll vs int?)
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* array bounds
*/

• Subtask 1: 10 / 10
• Subtask 2: 6 / 6
• Subtask 3: 30 / 30
• Subtask 4: 35 / 35
• Subtask 5: 19 / 19