Submission #587017

#	Time	Username	Problem	Language	Result	Execution time	Memory
587017		8e7	Reconstruction Project (JOI22_reconstruction)	C++17	3 / 100	5041 ms	1048576 KiB

reconstruction

//Challenge: Accepted
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
	while (l != r) cout << *l << " ", l++;
	cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 505
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
const int inf = 1<<30;
struct edge{
	int u, v, w;
	edge(){u = v = w = 0;}
	edge(int a, int b, int c){u = a, v = b, w = c;}
};

inline void del(vector<pii> &v, pii x) {
	v.erase(find(v.begin(), v.end(), x));
}
inline void del(vector<int> &v, int x) {
	v.erase(find(v.begin(), v.end(), x));
}
struct graph{
	vector<int> ed; //first < second
	vector<pii> adj[maxn];
	pii best;
	int bid, t;
	void init(int n) {
		ed.clear();
		t = 0;
		for (int i = 0;i <= n;i++) adj[i].clear();
	}
	bool getpath(int n, int par, int goal) {
		if (n == goal) return 1;
		for (auto [v, id]:adj[n]) {
			if (v != par && getpath(v, n, goal)) {
				if (id < bid) {
					bid = id;
					best = {n, v};
				}
				return 1;
			}
		}
		return 0;
	}
	void upd(int u, int v) {
		bid = inf;
		t++;
		if (u > v) swap(u, v);
		if (getpath(u, 0, v)) {
			if (best.ff > best.ss) swap(best.ff, best.ss);	
			del(adj[best.ff], make_pair(best.ss, bid));
			del(adj[best.ss], make_pair(best.ff, bid));
			del(ed, bid);
		}
		adj[u].push_back({v, t});
		adj[v].push_back({u, t});
		ed.push_back(t);
	}
} g;
vector<int> tree[100005];


struct DSU{
	int par[maxn], siz[maxn];	
	void init(int n) {
		for (int i = 1;i <= n;i++) par[i] = i, siz[i] = 1;
	}
	int find(int a) {
		return a == par[a] ? a : (par[a] = find(par[a]));
	}
	bool Union(int a, int b) {
		a = find(a), b = find(b);
		if (a == b) return 0;
		if (siz[a] < siz[b]) par[a] = b;
		else par[b] = a;
		return 1;
	}
} dsu;
int main() {
	io
	int n, m;
	cin >> n >> m;
	vector<edge> ed;
	for (int i = 0;i < m;i++) {
		int u, v, w;
		cin >> u >> v >> w;
		ed.push_back(edge(u, v, w));	
	}
	sort(ed.begin(), ed.end(), [&] (edge x, edge y){return x.w < y.w;});

	int q;
	cin >> q;
	vector<int> que, ques(q);
	for (int i = 0;i < q;i++) {
		cin >> ques[i];
	}
	for (int i = 0;i < m;i++) {
		for (int j = i+1;j < m;j++) {
			que.push_back((ed[i].w + ed[j].w)/2);
		}
	}
	if (que.size() == 0) que.push_back(0);
	que.push_back(inf);
	sort(que.begin(), que.end());
	que.resize(int(unique(que.begin(), que.end()) - que.begin()));	
	//for (int i = m - 1;i >= 0;i--) debug(ed[i].u, ed[i].v, ed[i].w);

	g.init(n);
	for (int i = m - 1;i >= 0;i--) {
		g.upd(ed[i].u, ed[i].v);
		tree[i] = g.ed;
	}
	g.init(n);
	int ind = 0, qid = 0;
	auto answer = [&] (int L, int id) {
		while (ind < que.size() && que[ind] < L) {
			//ll ans = 0;
			vector<int> &lef = g.ed, &rig = tree[id];
			vector<int> tmp;
			dsu.init(n);
			int p = (int)rig.size() - 1;

			auto addedge = [&] (edge &e) {
				if (dsu.Union(e.u, e.v)) tmp.push_back(e.w);
			};
			for (int i = (int)lef.size()-1;i >= 0;i--) {
				while (p >= 0 && abs(ed[m-rig[p]].w-que[ind]) < abs(ed[lef[i]-1].w-que[ind])) {
					addedge(ed[m-rig[p]]);
					p--;
				}
				addedge(ed[lef[i]-1]);
			}
			while (p >= 0) {
				addedge(ed[m-rig[p]]);
				p--;
			}
			while (qid < q && ques[qid] <= que[ind]) {
				ll ans = 0;
				for (int i:tmp) ans += abs(i - ques[qid]);
				cout << ans << "\n";
				qid++;
			}
			ind++;
		}
	};
	for (int i = 0;i < m;i++) {	
		answer(ed[i].w, i);
		g.upd(ed[i].u, ed[i].v);
	}
	answer(inf+1, m);
}

Compilation message (stderr)

reconstruction.cpp: In lambda function:
reconstruction.cpp:129:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |   while (ind < que.size() && que[ind] < L) {
      |          ~~~~^~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 0 / 4
• Subtask 3: 0 / 7
• Subtask 4: 0 / 28
• Subtask 5: 0 / 35
• Subtask 6: 0 / 23