Submission #798433

#	Time	Username	Problem	Language	Result	Execution time	Memory
798433		hugo_pm	Wild Boar (JOI18_wild_boar)	C++17	100 / 100	15781 ms	685616 KiB

wild_boar

#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

const int MAX_N = 2005, MAX_ARRET = 1 << 17;
int nbNode, nbEdge, nbReq, nbArret;
vector<int> adj[MAX_N];
int xorNode[MAX_N];
int poids[MAX_N];
int arrets[MAX_ARRET];
int vus[MAX_N][MAX_N];
int VuTime = 0;

struct Chemin {
	int len, fst, lst;
	bool operator<(const Chemin &oth) const {
		return tie(len, fst, lst) < tie(oth.len, oth.fst, oth.lst);
	}
	bool operator==(const Chemin &oth) const {
		return tie(len, fst, lst) == tie(oth.len, oth.fst, oth.lst);
	}
};

template<typename T>
using minpq = priority_queue<T, vector<T>, greater<T>>;

string to_string(const Chemin c) {
	return "(len=" + to_string(c.len) + ", fst=" + to_string(c.fst) + ", lst=" + to_string(c.lst) + ")";
}

int cntFirst[MAX_N + 1], cntLast[MAX_N + 1];
vector<Chemin> compressTab (vector<Chemin> &chemins) {
	#ifdef DEBUG
	assert(is_sorted(all(chemins)));
	#endif
	VuTime++;
	vector<Chemin> ret;
	for (Chemin chem : chemins) {
		if (ret.size() > 8)
			break;
		dbg(chem);
		if (cntFirst[1+chem.fst] == 3 or cntLast[1+chem.lst] == 3 or vus[1+chem.fst][1+chem.lst] == VuTime)
			continue;
		ret.push_back(chem);
		cntFirst[1+chem.fst]++;
		cntLast[1+chem.lst]++;
		vus[1+chem.fst][1+chem.lst] = VuTime;
	}
	for (Chemin chem : ret) {
		cntFirst[1+chem.fst]--;
		cntLast[1+chem.lst]--;
	}
	return ret;
};

/// i-eme feuille = candidats pour X[i] -> X[i+1]
vector<Chemin> tree[2*MAX_ARRET];
const int sizeTree = MAX_ARRET;
vector<Chemin> merge(const vector<Chemin> &v1, const vector<Chemin> &v2) {
	vector<Chemin> nv;
	for (const Chemin &c1 : v1) for (const Chemin &c2 : v2) {
		if (c1.lst != c2.fst) {
			int newFst = (c1.fst == -1 ? c2.fst : c1.fst);
			nv.push_back({c1.len + c2.len, newFst, c2.lst});
		}
	}
	sort(all(nv));
	return compressTab(nv);
}


int leftRightLeaf(int idx) {
	if (idx < sizeTree) idx = 2*idx+1;
	while (idx < sizeTree) idx *= 2;
	return idx - sizeTree;
}
void _recalc(int idx) {
	if (leftRightLeaf(idx) >= nbArret-1) { // todo check
		tree[idx] = tree[2*idx];
	} else {
		tree[idx] = merge(tree[2*idx], tree[2*idx+1]);
	}
}
void buildTree() {
	for (int node = sizeTree-1; node >= 1; --node) {
		_recalc(node);
	}
}

void update(int idx, vector<Chemin> v) {
	idx += sizeTree;
	tree[idx] = v;
	int lvl = 0;
	while (idx > 1) {
		idx /= 2;
		if (((2*idx+1) << lvl) - sizeTree >= nbArret-1) { // todo check
			tree[idx] = tree[2*idx];
		} else {
			tree[idx] = merge(tree[2*idx], tree[2*idx+1]);
		}
		++lvl;
	}
}

vector<Chemin> matrice[MAX_N][MAX_N];
void buildMatrice() {
	auto interesting = [&] (const Chemin &add, vector<Chemin> &V) {
		V.insert(upper_bound(all(V), add), add);
		V = compressTab(V);
		return (find(all(V), add) != end(V));
	};
	rep(depart, 0, nbNode) {
		auto& cand = matrice[depart];
		cand[depart].push_back({0, -1, -1});
		minpq<pair<Chemin, int>> pq;
		pq.push({cand[depart].back(), depart});
		vector<int> nbVus(nbNode);
		while (!pq.empty()) {
			auto [oldChemin, node] = pq.top();
			pq.pop();
			nbVus[node]++;
			// oldChemin.len == dist[node]
			dbg(depart, node);
			if (find(all(cand[node]), oldChemin) == end(cand[node])) {
				continue;
			}
			for (int iEdge : adj[node]) {
				if (iEdge == oldChemin.lst) continue;
				int voisin = xorNode[iEdge]^node;
				Chemin nouvChemin {
					oldChemin.len + poids[iEdge],
					(oldChemin.fst == -1 ? iEdge : oldChemin.fst),
					iEdge
				};
				if (interesting(nouvChemin, cand[voisin])) {
					dbg(voisin, cand[voisin], nouvChemin);
					pq.push({nouvChemin, voisin});
				}
			}
		}
		rep(node, 0, nbNode) {
			cand[node] = compressTab(cand[node]);
			assert(sz(cand[node]) <= 9);
		}
	}
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> nbNode >> nbEdge >> nbReq >> nbArret;
	rep(iEdge, 0, nbEdge) {
		int u, v; cin >> u >> v;
		--u, --v;
		cin >> poids[iEdge];
		xorNode[iEdge] = u^v;
		adj[u].push_back(iEdge);
		adj[v].push_back(iEdge);
	}
	buildMatrice();
	rep(iArret, 0, nbArret) {
		cin >> arrets[iArret];
		--arrets[iArret];
		if (iArret > 0) {
			tree[sizeTree + iArret-1] = matrice[arrets[iArret-1]][arrets[iArret]];
		}
	}
	buildTree();
	rep(iReq, 0, nbReq) {
		int indice, val;
		cin >> indice >> val;
		--indice, --val;
		arrets[indice] = val;
		if (indice > 0) {
			update(indice-1, matrice[arrets[indice-1]][arrets[indice]]);
		}
		if (indice+1 < nbArret) {
			update(indice, matrice[arrets[indice]][arrets[indice+1]]);
		}
		int ans = -1;
		if (!tree[1].empty()) ans = tree[1].front().len;
		cout << ans << '\n';	
	}
}

• Subtask 1: 12 / 12
• Subtask 2: 35 / 35
• Subtask 3: 15 / 15
• Subtask 4: 38 / 38