Submission #810913

#	Time	Username	Problem	Language	Result	Execution time	Memory
810913		hugo_pm	Reconstruction Project (JOI22_reconstruction)	C++17	100 / 100	1092 ms	30408 KiB

reconstruction

#include <bits/stdc++.h>
#define int long long
using namespace std;
	
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define sz(v) ((int)((v).size()))
	
template<typename T>
void chmax(T &x, const T &v) { if (x < v) x = v; }
template<typename T>
void chmin(T &x, const T &v) { if (x > v) x = v; }
	
using pii = pair<int, int>;
using vi = vector<int>;
	
string to_string(string s) { return s; }
template <typename T> string to_string(T v) {
	bool first = true;
	string res = "[";
	for (const auto &x : v) {
		if (!first)
			res += ", ";
		first = false;
		res += to_string(x);
	}
	res += "]";
	return res;
}
	
template <typename A, typename B>
string to_string(pair<A, B> p) {
	return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
	
void dbg_out() { cout << endl; }
template <typename Head, typename... Tail> void dbg_out(Head H, Tail... T) {
	cout << ' ' << to_string(H);
	dbg_out(T...);
}
	
#ifdef DEBUG
#define dbg(...) cout << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif
	
struct uf {
	int N;
	vector<int> repr, taille;
	void rebuild() {
		iota(repr.begin(), repr.end(), 0);
		taille.assign(N, 1);
	}
	uf(int _N) : N(_N), repr(_N) {
		rebuild();
	}
	int find(int u) {
		if (repr[u] == u) return u;
		return repr[u] = find(repr[u]);
	}
	bool unite(int u, int v) {
		u = find(u), v = find(v);
		if (u == v) return false;
		if (taille[u] < taille[v]) swap(u, v);
		repr[v] = u;
		taille[u] += taille[v];
		return true;
	}
};
struct Edge {
	int u, v, p;
};
int nbNode, nbEdge, nbReq;
vector<Edge> edges;
vector<pii> reqs;
struct MST {
	int cntDown = 0, sumDown = 0, cntUp = 0, sumUp = 0, cntEgal = 0, sumEgal = 0;
	int egalDown(int X) {
		// up - X, X - down
		return sumUp - sumDown - sumEgal + (cntEgal+cntDown - cntUp)*X;
	}
	int egalUp(int X) {
		// up - X, X - down
		return sumUp - sumDown + sumEgal + (-cntEgal+cntDown - cntUp)*X;
	}
};
	
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> nbNode >> nbEdge;
	edges.resize(nbEdge);
	for (auto &[u,v,p] : edges) {
		cin >> u >> v >> p;
		--u, --v;
		p *= 2;
	}
	auto compZero = [&] (Edge a, Edge b) { return a.p < b.p; };
	sort(all(edges), compZero);
	
	vector<vi> adjTree(nbNode);
	auto add = [&] (int iEdge) {
		const auto [u,v,_] = edges[iEdge];
		adjTree[u].push_back(iEdge);
		adjTree[v].push_back(iEdge);
	};
	auto remove = [&] (int iEdge) {
		const auto [u,v,_] = edges[iEdge];
		for (int c : {u, v})
			adjTree[c].erase(find(all(adjTree[c]), iEdge));
	};
	auto Dfs = [&] (auto dfs, int node, int parent, int dest, pii &ans) -> bool {
		if (node == dest) {
			return true;
		}
		for (int iEdge : adjTree[node]) {
			const auto [u,v,p] = edges[iEdge];
			int child = u^v^node;
			if (child == parent) continue;
			if(dfs(dfs, child, node, dest, ans)) {
				chmin(ans, make_pair(p, iEdge));
				return true;
			}
		}
		return false;
	};
	vector<pii> events;
	int realAdds = 0;
	rep(iCur, 0, nbEdge) {
		auto &cur = edges[iCur];
		pii ret {1e18, 0};
		if (Dfs(Dfs, cur.u, -1, cur.v, ret)) {
			auto [minTime, argMin] = ret;
			int betterTime = (cur.p + minTime)/2;
			remove(argMin);
			add(iCur);
			events.emplace_back(betterTime, minTime);
			events.emplace_back(betterTime, -cur.p);
		} else if (realAdds < nbNode-1) {
			++realAdds;
			add(iCur);
			events.emplace_back(0, -cur.p);
		}
	}
	sort(all(events));
	cin >> nbReq;
	vector<int> curMst;
	int ptr = 0;
	rep(iReq, 0, nbReq) {
		int X; cin >> X; X *= 2;
		while (ptr < sz(events) && events[ptr].first <= X) {
			int u = events[ptr].second;
			if (u < 0)
				curMst.push_back(-u);
			else
				curMst.erase(find(all(curMst), u)); 
			++ptr;
		}
		int ans = 0;
		for (int p : curMst) {
			ans += abs(p-X);
		}
		cout << ans/2 << '\n';
	}
}

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