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Submission #410557

# Submission time Handle Problem Language Result Execution time Memory
410557 2021-05-23T02:00:30 Z ngpin04 Olympic Bus (JOI20_ho_t4) C++14
100 / 100
 84 ms 5324 KB 
#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define int long long 
using namespace std;
const int N = 205;
const int M = 5e4 + 5; 
const int oo = 1e18;
 
vector <int> adj[N];
vector <int> newadj[N];
 
pair <int, int> edge[M];
 
int dis[N][N];
int newdis[N][N];
int d[N];
int f[M];
int g[M];
int par[N];
int cost[M];
int revcost[M];
int n,m;
 
bool vis[N];
bool flag[M];
 
template <typename T> 
bool mini(T &a, T b) {
	if (a > b) {
		a = b;
		return true;
	}
	return false;
}
 
void dfs(int u, int p) {
	par[u] = p;
	for (int id : newadj[u]) {
		int v = edge[id].se;
		d[v] = d[u] + 1;
		dfs(v, id);
	} 
}
 
void solve(int f[], int s, int t) {
	for (int i = 1; i <= n; i++) {
		vis[i] = false;
		newadj[i].clear();
	}
 
	for (int i = 1; i <= m; i++)
		flag[i] = false;
 
	queue <int> q({s});
	vis[s] = true;
	while (q.size()) {
		int u = q.front();
		q.pop();
		for (int id : adj[u]) {
			int v = edge[id].se;
			if (!vis[v] && dis[s][u] + cost[id] == dis[s][v]) {
				vis[v] = true;
				q.push(v);
				newadj[u].push_back(id);
				//cerr << s << " " << t << " " << id << "\n";
			}
		}
	}
 
	if (!vis[t]) {
		for (int i = 1; i <= m; i++) 
			f[i] = oo;
		return;	
	}
 
	d[s] = 0;
	dfs(s, -1);
 	
	vector <int> node;
	for (int u = t; u != s; u = edge[par[u]].fi) {
		node.push_back(u);
		flag[par[u]] = true;
	}
	node.push_back(s);
	reverse(node.begin(), node.end());

	for (int i = 1; i <= n; i++)
	for (int j = 1; j <= n; j++)
		if (i != j)
			newdis[i][j] = oo;

	for (int i =  1; i <= m; i++) {
		if (!flag[i]) {
			mini(newdis[edge[i].fi][edge[i].se], cost[i]);
			f[i] = dis[s][t];
		} else 
			f[i] = oo;
	}

	for (int j = 1; j <= n; j++)
	for (int i = 1; i <= n; i++)
	for (int k = 1; k <= n; k++)
		mini(newdis[i][k], newdis[i][j] + newdis[j][k]);

	for (int l = 0; l < (int) node.size(); l++)
	for (int r = l + 1; r < (int) node.size(); r++) {
		int u = node[l];
		int v = node[r];
		int res = dis[s][u] + newdis[u][v] + dis[v][t];
		for (; v != u; v = edge[par[v]].fi) 
			mini(f[par[v]], res);
	}
}
 
signed main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> m;
	for (int i = 1; i <= m; i++)
		cin >> edge[i].fi >> edge[i].se >> cost[i] >> revcost[i];
	
	for (int i = 1; i <= n; i++)
	for (int j = 1; j <= n; j++)
		if (i != j)
			dis[i][j] = oo;
 
	for (int i = 1; i <= m; i++)  {
		int u = edge[i].fi;
		int v = edge[i].se;
		mini(dis[u][v], cost[i]); 
		adj[u].push_back(i);
	}
 
	for (int j = 1; j <= n; j++)
	for (int i = 1; i <= n; i++)
	for (int k = 1; k <= n; k++) 
		mini(dis[i][k], dis[i][j] + dis[j][k]);
 
	// for (int i = 1; i <= n; i++)
	// for (int j = 1; j <= n; j++)
	// 	cerr << i << " " << j << " " << dis[i][j] << "\n"
 
	int ans = 2 * oo;
	if (dis[1][n] < oo && dis[n][1] < oo)
		ans = min(ans, dis[1][n] + dis[n][1]);
 
	solve(f, 1, n);
	solve(g, n, 1);
 
	// for (int i = 1; i <= m; i++)
	// 	cerr << f[i] << " \n"[i == m];
 
	// for (int i = 1; i <= m; i++) 
	// 	cerr << g[i] << " \n"[i == m];
 	
	for (int i = 1; i <= m; i++) {
		int u = edge[i].fi;
		int v = edge[i].se;
		int l = f[i];
		int r = g[i];
		if (dis[1][n] > dis[1][v] + dis[u][n] + cost[i]) 
			l = dis[1][v] + dis[u][n] + cost[i];
 
		if (dis[n][1] > dis[n][v] + dis[u][1] + cost[i])
			r = dis[n][v] + dis[u][1] + cost[i];
 
		// cerr << i << " " << l << " " << r << "\n";
 
		mini(ans, l + r + revcost[i]);
	}
 
	if (ans > 1e17)
		ans = -1;
	cout << ans;
	return 0;	
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 972 KB Output is correct
2 Correct 11 ms 688 KB Output is correct
3 Correct 42 ms 1176 KB Output is correct
4 Correct 43 ms 1060 KB Output is correct
5 Correct 2 ms 460 KB Output is correct
6 Correct 11 ms 688 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 332 KB Output is correct
10 Correct 53 ms 1072 KB Output is correct
11 Correct 53 ms 1064 KB Output is correct
12 Correct 52 ms 1056 KB Output is correct
13 Correct 14 ms 716 KB Output is correct
14 Correct 24 ms 1072 KB Output is correct
15 Correct 25 ms 972 KB Output is correct
16 Correct 26 ms 996 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 68 ms 4972 KB Output is correct
2 Correct 68 ms 5092 KB Output is correct
3 Correct 71 ms 5224 KB Output is correct
4 Correct 41 ms 1156 KB Output is correct
5 Correct 37 ms 972 KB Output is correct
6 Correct 10 ms 696 KB Output is correct
7 Correct 9 ms 688 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 35 ms 3804 KB Output is correct
10 Correct 35 ms 3756 KB Output is correct
11 Correct 49 ms 4164 KB Output is correct
12 Correct 49 ms 4144 KB Output is correct
13 Correct 50 ms 4224 KB Output is correct
14 Correct 50 ms 4160 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 1088 KB Output is correct
2 Correct 27 ms 1040 KB Output is correct
3 Correct 53 ms 3244 KB Output is correct
4 Correct 9 ms 588 KB Output is correct
5 Correct 58 ms 4028 KB Output is correct
6 Correct 1 ms 332 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 31 ms 3640 KB Output is correct
9 Correct 31 ms 3616 KB Output is correct
10 Correct 45 ms 4012 KB Output is correct
11 Correct 44 ms 4032 KB Output is correct
12 Correct 45 ms 4052 KB Output is correct
13 Correct 1 ms 332 KB Output is correct
14 Correct 1 ms 332 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 1 ms 332 KB Output is correct
17 Correct 1 ms 332 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 44 ms 4104 KB Output is correct
20 Correct 44 ms 3932 KB Output is correct
21 Correct 44 ms 4076 KB Output is correct
22 Correct 44 ms 3996 KB Output is correct

Subtask #4
63.0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 972 KB Output is correct
2 Correct 11 ms 688 KB Output is correct
3 Correct 42 ms 1176 KB Output is correct
4 Correct 43 ms 1060 KB Output is correct
5 Correct 2 ms 460 KB Output is correct
6 Correct 11 ms 688 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 332 KB Output is correct
10 Correct 53 ms 1072 KB Output is correct
11 Correct 53 ms 1064 KB Output is correct
12 Correct 52 ms 1056 KB Output is correct
13 Correct 14 ms 716 KB Output is correct
14 Correct 24 ms 1072 KB Output is correct
15 Correct 25 ms 972 KB Output is correct
16 Correct 26 ms 996 KB Output is correct
17 Correct 68 ms 4972 KB Output is correct
18 Correct 68 ms 5092 KB Output is correct
19 Correct 71 ms 5224 KB Output is correct
20 Correct 41 ms 1156 KB Output is correct
21 Correct 37 ms 972 KB Output is correct
22 Correct 10 ms 696 KB Output is correct
23 Correct 9 ms 688 KB Output is correct
24 Correct 1 ms 332 KB Output is correct
25 Correct 35 ms 3804 KB Output is correct
26 Correct 35 ms 3756 KB Output is correct
27 Correct 49 ms 4164 KB Output is correct
28 Correct 49 ms 4144 KB Output is correct
29 Correct 50 ms 4224 KB Output is correct
30 Correct 50 ms 4160 KB Output is correct
31 Correct 37 ms 1088 KB Output is correct
32 Correct 27 ms 1040 KB Output is correct
33 Correct 53 ms 3244 KB Output is correct
34 Correct 9 ms 588 KB Output is correct
35 Correct 58 ms 4028 KB Output is correct
36 Correct 1 ms 332 KB Output is correct
37 Correct 1 ms 332 KB Output is correct
38 Correct 31 ms 3640 KB Output is correct
39 Correct 31 ms 3616 KB Output is correct
40 Correct 45 ms 4012 KB Output is correct
41 Correct 44 ms 4032 KB Output is correct
42 Correct 45 ms 4052 KB Output is correct
43 Correct 1 ms 332 KB Output is correct
44 Correct 1 ms 332 KB Output is correct
45 Correct 1 ms 332 KB Output is correct
46 Correct 1 ms 332 KB Output is correct
47 Correct 1 ms 332 KB Output is correct
48 Correct 1 ms 332 KB Output is correct
49 Correct 44 ms 4104 KB Output is correct
50 Correct 44 ms 3932 KB Output is correct
51 Correct 44 ms 4076 KB Output is correct
52 Correct 44 ms 3996 KB Output is correct
53 Correct 71 ms 4932 KB Output is correct
54 Correct 75 ms 4936 KB Output is correct
55 Correct 78 ms 4996 KB Output is correct
56 Correct 40 ms 1100 KB Output is correct
57 Correct 40 ms 972 KB Output is correct
58 Correct 80 ms 4120 KB Output is correct
59 Correct 82 ms 4152 KB Output is correct
60 Correct 84 ms 4216 KB Output is correct
61 Correct 73 ms 4164 KB Output is correct
62 Correct 81 ms 4164 KB Output is correct
63 Correct 83 ms 4100 KB Output is correct
64 Correct 83 ms 4264 KB Output is correct
65 Correct 79 ms 4220 KB Output is correct
66 Correct 79 ms 4316 KB Output is correct
67 Correct 18 ms 3532 KB Output is correct
68 Correct 35 ms 4832 KB Output is correct
69 Correct 35 ms 4816 KB Output is correct
70 Correct 49 ms 5168 KB Output is correct
71 Correct 49 ms 5168 KB Output is correct
72 Correct 50 ms 5324 KB Output is correct
73 Correct 51 ms 5200 KB Output is correct
74 Correct 52 ms 5248 KB Output is correct