oj.uz

Submission #55270

# Submission time Handle Problem Language Result Execution time Memory
55270 2018-07-06T19:45:06 Z shoemakerjo Commuter Pass (JOI18_commuter_pass) C++14
100 / 100
 580 ms 147048 KB 
#include <bits/stdc++.h>

using namespace std;

#define maxn 100010
#define ll long long
#define pil pair<ll, ll>
#define pli pair<ll, ll>

int N, M;
int s, t, u, v;

const ll inf = 1LL << 61; //feels big enough

ll dists[maxn], distu[maxn], distv[maxn], distt[maxn], dists2[maxn]; 
bool onpath[maxn]; //starts out as false
bool vis[maxn];
ll smallu[maxn], smallv[maxn]; //store the minimum crossing
//run a triple dijkstra

vector<vector<pil>> adj(maxn);

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin >> N >> M >> s >> t >> u >> v;
	int a, b;
	ll c;
	for (int i = 0; i < M; i++) {
		cin >> a >> b >> c;
		adj[a].push_back(pil(b, c));
		adj[b].push_back(pil(a, c));
	}
	//guaranteed graph is connected
	priority_queue<pli, vector<pli>, greater<pli>> pq;

	fill(dists, dists+maxn, inf);
	fill(distu, distu+maxn, inf);
	fill(distv, distv+maxn, inf);
	fill(distt, distt+maxn, inf);
	dists[s] = 0;
	distu[u] = 0;
	distv[v] = 0;
	distt[t] = 0;
	pq.push(pli(0, s));
	while (pq.size()) {
		pil cur = pq.top(); pq.pop();
		int x = cur.second;
		ll d = cur.first;
		if (d > dists[x]) continue;
		for (pil nx : adj[x]) {
			if (d + nx.second < dists[nx.first]) {
				dists[nx.first] = d + nx.second;
				pq.push(pil(dists[nx.first], nx.first));
			}
		}
	}
	//now we run it for u and then we will do v
	pq.push(pli(0, u));
	while (pq.size()) {
		pil cur = pq.top(); pq.pop();
		int x = cur.second;
		ll d = cur.first;
		if (d > distu[x]) continue;
		for (pil nx : adj[x]) {
			if (d + nx.second < distu[nx.first]) {
				distu[nx.first] = d + nx.second;
				pq.push(pil(distu[nx.first], nx.first));
			}
		}
	}
	pq.push(pli(0, v));
	while (pq.size()) {
		pil cur = pq.top(); pq.pop();
		int x = cur.second;
		ll d = cur.first;
		if (d > distv[x]) continue;
		for (pil nx : adj[x]) {
			if (d + nx.second < distv[nx.first]) {
				distv[nx.first] = d + nx.second;
				pq.push(pil(distv[nx.first], nx.first));
			}
		}
	}

	ll ans = distu[v]; //maybe nothing is on the path
	//now we have to find what is on the path and then we can do the dp thing
	//we can do the dp by just doing another dijkstra from s b/c easy
	//to calculate what is on the path we might want to dijkstra from t??
	onpath[t] = true; // we know that
	//run a modified dijkstra from t, only adding things if they are on the path
	vis[t] = true;
	pq.push(pli(0, t));
	while (pq.size()) {
		pil cur = pq.top(); pq.pop();
		int x= cur.second;
		if (x == s) break; //no need to go further
		ll d = cur.first;
		if (d > distt[x]) continue;
		for (pil nx : adj[x]) {
			if (dists[nx.first] + nx.second != dists[x]) {
				continue; //not on path
			}
			onpath[nx.first] = true;
			if (d + nx.second < distt[nx.first]) {
				distt[nx.first] = d + nx.second;
				pq.push(pil(distt[nx.first], nx.first));
			}
		}
	}
	//now we do the dp stuff
	fill(dists2, dists2+maxn, inf);
	fill(smallu, smallu+maxn, inf);
	fill(smallv, smallv+maxn, inf);
	dists2[s] = 0LL;
	pq.push(pli(0, s));
	while (pq.size()) {
		pil cur = pq.top(); pq.pop();
		int x = cur.second;
		ll d = cur.first;
		if (d > dists2[x]) continue;
	//	cout << "gotten here: " << x << endl;
		smallu[x] = min(smallu[x], distu[x]);
		smallv[x] = min(smallv[x], distv[x]);
		ans = min(ans, smallv[x] + distu[x]);
		ans = min(ans, smallu[x] + distv[x]);
		//process from parents when we go down
		for (pil nx : adj[x]) {
			if (!onpath[nx.first]) continue;
			if (dists[x] + nx.second == dists[nx.first]) {
				smallu[nx.first] = min(smallu[nx.first], smallu[x]);
				smallv[nx.first] = min(smallv[nx.first], smallv[x]);
			}
			if (d + nx.second < dists2[nx.first]) {
				dists2[nx.first] = d + nx.second;
				pq.push(pil(dists2[nx.first], nx.first));
			}
		}

	}
	// for (int i = 1; i <= N; i++) {
	// 	if (onpath[i]) cout << i << " is on the path" << endl;
	// }

	//cout << "printing dist s stuff" << endl;
	// for (int i = 1; i <= N; i++) {
	// 	cout << "     " << dists[i] << endl;
	// }

	//right now i should give <= correct 
	//have to modify the min calculation stuff (should not be hard though)
	// cout << "dist u: " << distu[t] << endl;
	// cout << "dist v: " << distv[t] << endl;
	// cout << "dist s: " << dists[t] << endl;
	// cout << "small u: " << smallu[t] << endl;
	// cout << "small v: " << smallv[t] << endl;
	cout << ans << endl;

}

Subtask #1
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 410 ms 23912 KB Output is correct
2 Correct 445 ms 27380 KB Output is correct
3 Correct 570 ms 30876 KB Output is correct
4 Correct 385 ms 35064 KB Output is correct
5 Correct 496 ms 38548 KB Output is correct
6 Correct 342 ms 42656 KB Output is correct
7 Correct 540 ms 45744 KB Output is correct
8 Correct 476 ms 49312 KB Output is correct
9 Correct 424 ms 53396 KB Output is correct
10 Correct 384 ms 57840 KB Output is correct
11 Correct 299 ms 57840 KB Output is correct
12 Correct 435 ms 64160 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 487 ms 68248 KB Output is correct
2 Correct 491 ms 71504 KB Output is correct
3 Correct 479 ms 75060 KB Output is correct
4 Correct 486 ms 78664 KB Output is correct
5 Correct 487 ms 81960 KB Output is correct
6 Correct 558 ms 85628 KB Output is correct
7 Correct 552 ms 89232 KB Output is correct
8 Correct 487 ms 92716 KB Output is correct
9 Correct 503 ms 96132 KB Output is correct
10 Correct 502 ms 99732 KB Output is correct
11 Correct 247 ms 99732 KB Output is correct
12 Correct 557 ms 105372 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 105372 KB Output is correct
2 Correct 9 ms 105372 KB Output is correct
3 Correct 9 ms 105372 KB Output is correct
4 Correct 45 ms 105372 KB Output is correct
5 Correct 29 ms 105372 KB Output is correct
6 Correct 10 ms 105372 KB Output is correct
7 Correct 11 ms 105372 KB Output is correct
8 Correct 13 ms 105372 KB Output is correct
9 Correct 11 ms 105372 KB Output is correct
10 Correct 27 ms 105372 KB Output is correct
11 Correct 11 ms 105372 KB Output is correct
12 Correct 9 ms 105372 KB Output is correct
13 Correct 11 ms 105372 KB Output is correct
14 Correct 11 ms 105372 KB Output is correct
15 Correct 10 ms 105372 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 410 ms 23912 KB Output is correct
2 Correct 445 ms 27380 KB Output is correct
3 Correct 570 ms 30876 KB Output is correct
4 Correct 385 ms 35064 KB Output is correct
5 Correct 496 ms 38548 KB Output is correct
6 Correct 342 ms 42656 KB Output is correct
7 Correct 540 ms 45744 KB Output is correct
8 Correct 476 ms 49312 KB Output is correct
9 Correct 424 ms 53396 KB Output is correct
10 Correct 384 ms 57840 KB Output is correct
11 Correct 299 ms 57840 KB Output is correct
12 Correct 435 ms 64160 KB Output is correct
13 Correct 487 ms 68248 KB Output is correct
14 Correct 491 ms 71504 KB Output is correct
15 Correct 479 ms 75060 KB Output is correct
16 Correct 486 ms 78664 KB Output is correct
17 Correct 487 ms 81960 KB Output is correct
18 Correct 558 ms 85628 KB Output is correct
19 Correct 552 ms 89232 KB Output is correct
20 Correct 487 ms 92716 KB Output is correct
21 Correct 503 ms 96132 KB Output is correct
22 Correct 502 ms 99732 KB Output is correct
23 Correct 247 ms 99732 KB Output is correct
24 Correct 557 ms 105372 KB Output is correct
25 Correct 28 ms 105372 KB Output is correct
26 Correct 9 ms 105372 KB Output is correct
27 Correct 9 ms 105372 KB Output is correct
28 Correct 45 ms 105372 KB Output is correct
29 Correct 29 ms 105372 KB Output is correct
30 Correct 10 ms 105372 KB Output is correct
31 Correct 11 ms 105372 KB Output is correct
32 Correct 13 ms 105372 KB Output is correct
33 Correct 11 ms 105372 KB Output is correct
34 Correct 27 ms 105372 KB Output is correct
35 Correct 11 ms 105372 KB Output is correct
36 Correct 9 ms 105372 KB Output is correct
37 Correct 11 ms 105372 KB Output is correct
38 Correct 11 ms 105372 KB Output is correct
39 Correct 10 ms 105372 KB Output is correct
40 Correct 414 ms 111404 KB Output is correct
41 Correct 431 ms 116052 KB Output is correct
42 Correct 393 ms 120224 KB Output is correct
43 Correct 253 ms 120224 KB Output is correct
44 Correct 255 ms 120224 KB Output is correct
45 Correct 540 ms 127776 KB Output is correct
46 Correct 510 ms 131080 KB Output is correct
47 Correct 524 ms 135268 KB Output is correct
48 Correct 336 ms 135268 KB Output is correct
49 Correct 377 ms 140008 KB Output is correct
50 Correct 580 ms 143680 KB Output is correct
51 Correct 561 ms 147048 KB Output is correct