Submission #724728

#	Time	Username	Problem	Language	Result	Execution time	Memory
724728		GusterGoose27	Wild Boar (JOI18_wild_boar)	C++17	12 / 100	136 ms	36768 KiB

wild_boar

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, bool> plb;
typedef pair<ll, int> pli;

const int MAXN = 2000;
const int MAXM = 12000;
const int MAX_PATH = 1e5;
const ll inf = 1e15;

class path {
public:
	ll len;
	int s, e;
	path(ll l, int s, int e) : len(l), s(s), e(e) {}
	path() {}
};

vector<int> edges[MAXN];
pii init_edge[2*MAXN]; // dest, weight
vector<int> dual[MAXM];
int ecount = 0;

int make_edge() {
	return (ecount++);
}

path dist[MAXN][MAXN][5]; // 0 : normal, 1 : first diff, 2 : f/e, 3 : e, 4 : e/f
ll edge_dist[2*MAXN][2*MAXN];
bool vis[MAXM]; // bitset?
int seq[MAX_PATH];
int n, m, t, l;

path min(path a, path b) {
	if (a.len <= b.len) return a;
	return b;
}

path comb(path a, path b) {
	assert(a.e != b.s);
	if (a.len == inf || b.len == inf) return path(inf, -1, -2);
	return path(a.len+b.len, a.s, b.e);
}

class stree {
public:
	int lp, rp;
	stree *l = nullptr;
	stree *r = nullptr;
	path seg[5];
	stree(int lv, int rv) {
		lp = lv;
		rp = rv;
		if (lp < rp) {
			int mid = (lp+rp)/2;
			l = new stree(lp, mid);
			r = new stree(mid+1, rp);
		}
		make();
	}
	int rdiff(int a) {
		if (a == 0) return 3;
		return 2;
	}
	void avoid(path seg[], int s, int e, int &a) { // best path avoiding these things
		if (seg[a].s == s) a = 1;
		if (seg[a].e == e) a = rdiff(a);
		if (seg[a].s == s) a++;
	}
	void make() { // really slow. Could probably be faster
		if (lp == rp) {
			for (int i = 0; i < 5; i++) seg[i] = dist[seq[lp]][seq[lp+1]][i];
			return;
		}
		for (int i = 0; i < 5; i++) {
			int a = 0, b = 0;
			int lv = -2, rv = -2;
			if (i == 1 || i == 2) lv = seg[0].s;
			if (i == 4) lv = seg[3].s;
			if (i == 2) rv = seg[1].e;
			if (i == 3 || i == 4) rv = seg[0].e;
			avoid(l->seg, lv, -2, a);
			avoid(r->seg, l->seg[a].e, rv, b);
			seg[i] = comb(l->seg[a], r->seg[b]);
			a = 0, b = 0;
			avoid(r->seg, -2, rv, b);
			avoid(l->seg, lv, r->seg[b].s, a);
			seg[i] = min(seg[i], comb(l->seg[a], r->seg[b]));
		}
	}
	void upd(int p) {
		if (lp > p || rp < p) return;
		if (lp == rp) return make();
		l->upd(p);
		r->upd(p);
		make();
	}
};

stree *tree;

void dijkstra(int s) {
	fill(edge_dist[s], edge_dist[s]+2*m, inf);
	fill(vis, vis+MAXM, 0); // could optimize by expanding dists to make pq smaller
	priority_queue<pli, vector<pli>, greater<pli>> pq;
	pq.push(pli(init_edge[s].second, s));
	while (!pq.empty()) {
		pli tp = pq.top();
		pq.pop();
		if (vis[tp.second]) continue;
		if (tp.second < 2*m) edge_dist[s][tp.second] = tp.first;
		vis[tp.second] = 1;
		for (int nxt: dual[tp.second]) {
			if (vis[nxt]) continue;
			ll ndist = tp.first+((nxt<2*m) ? init_edge[nxt].second : 0);
			pq.push(pli(ndist, nxt));
		}
	}
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> m >> t >> l;
	for (int i = 0; i < m; i++) {
		int a, b, c;
		cin >> a >> b >> c; a--; b--;
		init_edge[2*i] = pii(b, c);
		init_edge[2*i+1] = pii(a, c);
		edges[a].push_back(make_edge());
		edges[b].push_back(make_edge());
	}
	for (int i = 0; i < n; i++) {
		vector<int> pref;
		vector<int> suf;
		for (int j = 0; j < edges[i].size(); j++) {
			pref.push_back(make_edge());
			dual[pref.back()].push_back(edges[i][j]);
		}
		for (int j = 0; j < edges[i].size(); j++) {
			suf.push_back(make_edge());
			dual[suf.back()].push_back(edges[i][j]);
		}
		for (int j = 1; j < edges[i].size(); j++) {
			dual[pref[j]].push_back(pref[j-1]);
			dual[suf[j-1]].push_back(suf[j]);
		}
		for (int j = 0; j < edges[i].size(); j++) {
			if (j)dual[edges[i][j]^1].push_back(pref[j-1]);
			if (j<edges[i].size()-1)dual[edges[i][j]^1].push_back(suf[j+1]);
		}
	}
	for (int i = 0; i < 2*m; i++) dijkstra(i); // much cleaner?
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			dist[i][j][0] = path(inf, -1, -2);
			for (int a: edges[i]) {
				for (int b: edges[j]) {
					dist[i][j][0] = min(dist[i][j][0], path(edge_dist[a][b^1], a, b));
				}
			}
			// 1
			dist[i][j][1] = path(inf, -1, -2);
			for (int a: edges[i]) {
				if (a == dist[i][j][0].s) continue;
				for (int b: edges[j]) {
					dist[i][j][1] = min(dist[i][j][1], path(edge_dist[a][b^1], a, b));
				}
			}
			// 2
			dist[i][j][2] = path(inf, -1, -2);
			for (int a: edges[i]) {
				if (a == dist[i][j][0].s) continue;
				for (int b: edges[j]) {
					if (b == dist[i][j][1].e) continue;
					dist[i][j][2] = min(dist[i][j][2], path(edge_dist[a][b^1], a, b));
				}
			}
			// 3
			dist[i][j][3] = path(inf, -1, -2);
			for (int a: edges[i]) {
				for (int b: edges[j]) {
					if (b == dist[i][j][0].e) continue;
					dist[i][j][3] = min(dist[i][j][3], path(edge_dist[a][b^1], a, b));
				}
			}
			// 4
			dist[i][j][4] = path(inf, -1, -2);
			for (int a: edges[i]) {
				if (a == dist[i][j][3].s) continue;
				for (int b: edges[j]) {
					if (b == dist[i][j][0].e) continue;
					dist[i][j][4] = min(dist[i][j][4], path(edge_dist[a][b^1], a, b));
				}
			}
		}
	}
	for (int i = 0; i < l; i++) {
		cin >> seq[i];
		seq[i]--;
	}
	tree = new stree(0, l-2);
	for (int i = 0; i < t; i++) {
		int x, v; cin >> x >> v;
		x--; v--;
		seq[x] = v;
		if (x) tree->upd(x-1);
		if (x < l-1) tree->upd(x);
		if (tree->seg[0].len == inf) cout << "-1\n";
		else cout << tree->seg[0].len << "\n";
	}
	return 0;
}

Compilation message (stderr)

wild_boar.cpp: In function 'int main()':
wild_boar.cpp:138:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  138 |   for (int j = 0; j < edges[i].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~
wild_boar.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 |   for (int j = 0; j < edges[i].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~
wild_boar.cpp:146:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  146 |   for (int j = 1; j < edges[i].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~
wild_boar.cpp:150:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  150 |   for (int j = 0; j < edges[i].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~
wild_boar.cpp:152:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |    if (j<edges[i].size()-1)dual[edges[i][j]^1].push_back(suf[j+1]);
      |        ~^~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 0 / 35
• Subtask 3: 0 / 15
• Subtask 4: 0 / 38