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Submission #635323

# Submission time Handle Problem Language Result Execution time Memory
635323 2022-08-26T05:17:15 Z S2speed LOSTIKS (INOI20_lostiks) C++17
59 / 100
 2000 ms 399020 KB 
#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("Ofast")

#define sze(x) (ll)(x.size())
typedef long long ll;
typedef pair<ll , ll> pll;

const ll maxn = (1 << 20) + 17 , inf = 2e16;

ll n , s , t;
vector<pll> adj[maxn];
vector<ll> dis[maxn] , bfs;
ll g[maxn] , k[22] , d[22] , e[22] , dp[maxn][22];

void BFS(ll r , bool f = false){
	bfs.clear();
	dis[r].assign(n , inf);
	dis[r][r] = 0;
	g[r] = 0;
	bfs.push_back(r);
	ll x = 0;
	while(x < sze(bfs)){
		ll v = bfs[x++];
		for(auto p : adj[v]){
			ll i = p.first , t = p.second;
			if(dis[r][i] < dis[r][v] + 1) continue;
			if(f){
				g[i] = g[v];
				if(t != -1){
					g[i] ^= (1 << t);
					d[t] = v;
				}
			}
			dis[r][i] = dis[r][v] + 1;
			bfs.push_back(i);
		}
	}
	return;
}

int main(){
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);

	memset(dp , 63 , sizeof(dp));
	cin>>n>>s>>t; s--; t--;
	ll m = 0;
	for(ll i = 1 ; i < n ; i++){
		ll v , u , w;
		cin>>v>>u>>w; v--; u--; w--;
		if(w != -1){
			k[m] = w;
			adj[v].push_back({u , m}); adj[u].push_back({v , m});
			m++;
		} else {
			adj[v].push_back({u , w}); adj[u].push_back({v , w});
		}
	}
	BFS(s , true);
	if(g[t] == 0){
		cout<<dis[s][t]<<'\n';
		return 0;
	}
	for(ll j = 0 ; j < m ; j++){
		e[j] = g[k[j]] | g[d[j]];
		BFS(d[j]);
		if(e[j] == 0){
			dp[(1 << j)][j] = dis[s][k[j]] + dis[d[j]][k[j]];
		}
	}
	ll lm = (1 << m);
	for(ll mask = 1 ; mask < lm ; mask++){
		for(ll j = 0 ; j < m ; j++){
			if(mask & (1 << j)) continue;
			if((e[j] & mask) != e[j]) continue;
			ll h = inf;
			for(ll i = 0 ; i < m ; i++){
				if(!(mask & (1 << i))) continue;
				h = min(h , dp[mask][i] + dis[d[i]][k[j]] + dis[d[j]][k[j]]);
			}
			dp[mask ^ (1 << j)][j] = min(dp[mask ^ (1 << j)][j] , h);
		}
	}
//	cout<<dp[2][1]<<' '<<dp[6][2]<<' '<<dp[7][0]<<'\n';
//	cout<<dis[d[0]][t]<<'\n';
	ll ans = inf;
	for(ll mask = 1 ; mask < lm ; mask++){
		if((g[t] & mask) != g[t]) continue;
		ll h = inf;
		for(ll i = 0 ; i < m ; i++){
			if(!(mask & (1 << i))) continue;
//			cout<<mask<<' '<<i<<'\n';
			h = min(h , dp[mask][i] + dis[d[i]][t]);
		}
		ans = min(ans , h);
	}
	cout<<(ans == inf ? -1 : ans)<<'\n';
	return 0;
}

Subtask #1
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 99 ms 230012 KB Output is correct
2 Correct 89 ms 230048 KB Output is correct
3 Correct 174 ms 244676 KB Output is correct
4 Correct 181 ms 244560 KB Output is correct
5 Correct 168 ms 244672 KB Output is correct
6 Correct 185 ms 244520 KB Output is correct
7 Correct 191 ms 244572 KB Output is correct
8 Correct 171 ms 244512 KB Output is correct
9 Correct 173 ms 244496 KB Output is correct
10 Correct 170 ms 244604 KB Output is correct
11 Correct 170 ms 244588 KB Output is correct
12 Correct 163 ms 244048 KB Output is correct
13 Correct 167 ms 244108 KB Output is correct
14 Correct 171 ms 244288 KB Output is correct
15 Correct 163 ms 244144 KB Output is correct
16 Correct 160 ms 244168 KB Output is correct
17 Correct 153 ms 244088 KB Output is correct
18 Correct 157 ms 244172 KB Output is correct
19 Correct 149 ms 244172 KB Output is correct
20 Correct 147 ms 244140 KB Output is correct
21 Correct 144 ms 244108 KB Output is correct
22 Correct 97 ms 230124 KB Output is correct
23 Correct 92 ms 230120 KB Output is correct
24 Correct 93 ms 230056 KB Output is correct
25 Correct 91 ms 230160 KB Output is correct
26 Correct 89 ms 230072 KB Output is correct

Subtask #2
36.0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 92 ms 230092 KB Output is correct
2 Correct 89 ms 230136 KB Output is correct
3 Correct 89 ms 230112 KB Output is correct
4 Correct 88 ms 230068 KB Output is correct
5 Correct 225 ms 231680 KB Output is correct
6 Correct 196 ms 231692 KB Output is correct
7 Correct 254 ms 231800 KB Output is correct
8 Correct 203 ms 231688 KB Output is correct
9 Correct 221 ms 231800 KB Output is correct
10 Correct 155 ms 231788 KB Output is correct
11 Correct 155 ms 231672 KB Output is correct
12 Correct 159 ms 231792 KB Output is correct
13 Correct 156 ms 231792 KB Output is correct
14 Correct 155 ms 231752 KB Output is correct
15 Correct 211 ms 231740 KB Output is correct
16 Correct 233 ms 231708 KB Output is correct
17 Correct 215 ms 231708 KB Output is correct
18 Correct 154 ms 231764 KB Output is correct
19 Correct 158 ms 231680 KB Output is correct
20 Correct 158 ms 231884 KB Output is correct
21 Correct 155 ms 231688 KB Output is correct
22 Correct 155 ms 231736 KB Output is correct
23 Correct 157 ms 231756 KB Output is correct
24 Correct 155 ms 231656 KB Output is correct
25 Correct 735 ms 230200 KB Output is correct

Subtask #3
0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 99 ms 230012 KB Output is correct
2 Correct 89 ms 230048 KB Output is correct
3 Correct 174 ms 244676 KB Output is correct
4 Correct 181 ms 244560 KB Output is correct
5 Correct 168 ms 244672 KB Output is correct
6 Correct 185 ms 244520 KB Output is correct
7 Correct 191 ms 244572 KB Output is correct
8 Correct 171 ms 244512 KB Output is correct
9 Correct 173 ms 244496 KB Output is correct
10 Correct 170 ms 244604 KB Output is correct
11 Correct 170 ms 244588 KB Output is correct
12 Correct 163 ms 244048 KB Output is correct
13 Correct 167 ms 244108 KB Output is correct
14 Correct 171 ms 244288 KB Output is correct
15 Correct 163 ms 244144 KB Output is correct
16 Correct 160 ms 244168 KB Output is correct
17 Correct 153 ms 244088 KB Output is correct
18 Correct 157 ms 244172 KB Output is correct
19 Correct 149 ms 244172 KB Output is correct
20 Correct 147 ms 244140 KB Output is correct
21 Correct 144 ms 244108 KB Output is correct
22 Correct 97 ms 230124 KB Output is correct
23 Correct 92 ms 230120 KB Output is correct
24 Correct 93 ms 230056 KB Output is correct
25 Correct 91 ms 230160 KB Output is correct
26 Correct 89 ms 230072 KB Output is correct
27 Correct 92 ms 230092 KB Output is correct
28 Correct 89 ms 230136 KB Output is correct
29 Correct 89 ms 230112 KB Output is correct
30 Correct 88 ms 230068 KB Output is correct
31 Correct 225 ms 231680 KB Output is correct
32 Correct 196 ms 231692 KB Output is correct
33 Correct 254 ms 231800 KB Output is correct
34 Correct 203 ms 231688 KB Output is correct
35 Correct 221 ms 231800 KB Output is correct
36 Correct 155 ms 231788 KB Output is correct
37 Correct 155 ms 231672 KB Output is correct
38 Correct 159 ms 231792 KB Output is correct
39 Correct 156 ms 231792 KB Output is correct
40 Correct 155 ms 231752 KB Output is correct
41 Correct 211 ms 231740 KB Output is correct
42 Correct 233 ms 231708 KB Output is correct
43 Correct 215 ms 231708 KB Output is correct
44 Correct 154 ms 231764 KB Output is correct
45 Correct 158 ms 231680 KB Output is correct
46 Correct 158 ms 231884 KB Output is correct
47 Correct 155 ms 231688 KB Output is correct
48 Correct 155 ms 231736 KB Output is correct
49 Correct 157 ms 231756 KB Output is correct
50 Correct 155 ms 231656 KB Output is correct
51 Correct 735 ms 230200 KB Output is correct
52 Correct 1975 ms 383204 KB Output is correct
53 Execution timed out 2098 ms 399020 KB Time limit exceeded
54 Halted 0 ms 0 KB -