Submission #870999

#	Time	Username	Problem	Language	Result	Execution time	Memory
870999		marvinthang	Bridges (APIO19_bridges)	C++17	30 / 100	1545 ms	8776 KiB

bridges

/*************************************
*    author: marvinthang             *
*    created: 09.11.2023 22:50:14    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i-- > 0; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

const int BLOCK_SIZE = 320;

struct Edge {
	int u, v, w;
	Edge(int u, int v, int w): u(u), v(v), w(w) {}
	bool operator < (const Edge &other) const {	return w > other.w; }
};

struct Query {
	int t, u, w;
	Query(int t, int u, int w): t(t), u(u), w(w) {}
};

void process(void) {
	int n, m, q; cin >> n >> m;
	vector <Edge> edges;
	REP(i, m) {
		int u, v, w; cin >> u >> v >> w; --u; --v;
		edges.emplace_back(u, v, w);
	}
	vector <int> ord(m);
	iota(ALL(ord), 0);
	sort(ALL(ord), [&] (int a, int b) { return edges[a].w > edges[b].w; });
	vector <Query> queries;
	cin >> q;
	REP(i, q) {
		int t, u, w; cin >> t >> u >> w; --u;
		queries.emplace_back(t, u, w);
	}
	vector <int> par(n, -1);
	stack <pair <int, int>> his;
	function <int(int, bool)> find = [&] (int u, bool save) {
		if (par[u] < 0) return u;
		if (save) his.emplace(u, par[u]);
		return par[u] = find(par[u], save);
	};
	auto join = [&] (int u, int v, bool save) {
		if ((u = find(u, save)) == (v = find(v, save))) return false;
		if (par[u] > par[v]) swap(u, v);
		if (save) his.emplace(u, par[u]);
		if (save) his.emplace(v, par[v]);
		par[u] += par[v];
		par[v] = u;
		return true;
	};
	auto rollback = [&] {
		while (!his.empty()) {
			par[his.top().fi] = his.top().se;
			his.pop();
		}
	};
	vector <bool> used(m);
	vector <int> res(q, -1);
	for (int l = 0; l < q; ) {
		int r = min(q, l + BLOCK_SIZE);
		vector <int> qr;
		FOR(i, l, r) {
			if (queries[i].t == 1) used[queries[i].u] = true;
			else qr.push_back(i);
		}
		fill(ALL(par), -1);
		sort(ALL(qr), [&] (int a, int b) { return queries[a].w > queries[b].w; });
		int p = 0;
		for (int i: qr) {
			auto [t, u, w] = queries[i];
			while (p < m && edges[ord[p]].w >= w) {
				if (!used[ord[p]]) join(edges[ord[p]].u, edges[ord[p]].v, false);
				++p;
			}
			FORD(j, i, l) if (queries[j].t == 1 && queries[j].w >= w) {
				int x = queries[j].u;
				if (!used[x]) continue;
				used[x] = false;
				join(edges[x].u, edges[x].v, true);
			}
			FOR(j, i + 1, r) if (queries[j].t == 1) {
				int x = queries[j].u;
				if (!used[x] || edges[x].w < w) continue;
				used[x] = false;
				join(edges[x].u, edges[x].v, true);
			}
			FOR(j, l, r) if (queries[j].t == 1) used[queries[j].u] = true;
			res[i] = -par[find(u, true)];
			rollback();
		}
		vector <int> nxt;
		FORD(i, r, l) if (queries[i].t == 1) {
			int x = queries[i].u;
			if (!used[x]) continue;
			used[x] = false;
			edges[x].w = queries[i].w;
			nxt.push_back(x);
		}
		for (int i: nxt) used[i] = true;
		sort(ALL(nxt), [&] (int a, int b) { return edges[a].w > edges[b].w; });
		int i = 0, j = 0;
		vector <int> new_ord;
		while (i < m || j < nxt.size()) {
			if (i < m && used[ord[i]]) ++i;
			else if (i == m || (j < nxt.size() && edges[ord[i]].w <= edges[nxt[j]].w)) new_ord.push_back(nxt[j++]);
			else new_ord.push_back(ord[i++]);
		}
		for (int i: nxt) used[i] = false;
		ord = move(new_ord);
		l = r;
	}
	REP(i, q) if (res[i] != -1) cout << res[i] << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("bridges");
	// int t; cin >> t; while (t--)
	process();
	// cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message (stderr)

bridges.cpp: In function 'void process()':
bridges.cpp:142:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  142 |   while (i < m || j < nxt.size()) {
      |                   ~~^~~~~~~~~~~~
bridges.cpp:144:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  144 |    else if (i == m || (j < nxt.size() && edges[ord[i]].w <= edges[nxt[j]].w)) new_ord.push_back(nxt[j++]);
      |                        ~~^~~~~~~~~~~~
bridges.cpp: In function 'int main()':
bridges.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:156:2: note: in expansion of macro 'file'
  156 |  file("bridges");
      |  ^~~~
bridges.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:156:2: note: in expansion of macro 'file'
  156 |  file("bridges");
      |  ^~~~

• Subtask 1: 0 / 13
• Subtask 2: 16 / 16
• Subtask 3: 0 / 17
• Subtask 4: 14 / 14
• Subtask 5: 0 / 13
• Subtask 6: 0 / 27