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Submission #635324

# Submission time Handle Problem Language Result Execution time Memory
635324 2022-08-26T05:20:13 Z S2speed LOSTIKS (INOI20_lostiks) C++17
59 / 100
 2000 ms 232312 KB 
#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize ("Ofast")

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

const ll maxn = (1 << 20) + 17 , inf = 2e8;

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

void BFS(int r , bool f = false){
	bfs.clear();
	dis[r].assign(n , inf);
	dis[r][r] = 0;
	g[r] = 0;
	bfs.push_back(r);
	int x = 0;
	while(x < sze(bfs)){
		int v = bfs[x++];
		for(auto p : adj[v]){
			int 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--;
	int m = 0;
	for(int i = 1 ; i < n ; i++){
		int 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(int 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]];
		}
	}
	int lm = (1 << m);
	for(int mask = 1 ; mask < lm ; mask++){
		for(int j = 0 ; j < m ; j++){
			if(mask & (1 << j)) continue;
			if((e[j] & mask) != e[j]) continue;
			int h = inf;
			for(int 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';
	int ans = inf;
	for(int mask = 1 ; mask < lm ; mask++){
		if((g[t] & mask) != g[t]) continue;
		int h = inf;
		for(int 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 57 ms 139832 KB Output is correct
2 Correct 57 ms 139760 KB Output is correct
3 Correct 129 ms 148684 KB Output is correct
4 Correct 147 ms 148544 KB Output is correct
5 Correct 148 ms 148616 KB Output is correct
6 Correct 142 ms 148480 KB Output is correct
7 Correct 126 ms 148548 KB Output is correct
8 Correct 123 ms 148424 KB Output is correct
9 Correct 136 ms 148508 KB Output is correct
10 Correct 145 ms 148552 KB Output is correct
11 Correct 139 ms 148516 KB Output is correct
12 Correct 138 ms 147888 KB Output is correct
13 Correct 126 ms 148020 KB Output is correct
14 Correct 143 ms 147944 KB Output is correct
15 Correct 132 ms 148020 KB Output is correct
16 Correct 117 ms 147744 KB Output is correct
17 Correct 124 ms 147800 KB Output is correct
18 Correct 114 ms 147904 KB Output is correct
19 Correct 110 ms 147724 KB Output is correct
20 Correct 109 ms 147720 KB Output is correct
21 Correct 112 ms 147788 KB Output is correct
22 Correct 63 ms 139856 KB Output is correct
23 Correct 64 ms 139756 KB Output is correct
24 Correct 59 ms 139848 KB Output is correct
25 Correct 55 ms 139904 KB Output is correct
26 Correct 56 ms 139852 KB Output is correct

Subtask #2
36.0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 56 ms 139848 KB Output is correct
2 Correct 58 ms 139844 KB Output is correct
3 Correct 68 ms 139792 KB Output is correct
4 Correct 65 ms 139800 KB Output is correct
5 Correct 172 ms 140784 KB Output is correct
6 Correct 150 ms 140748 KB Output is correct
7 Correct 206 ms 140800 KB Output is correct
8 Correct 169 ms 140696 KB Output is correct
9 Correct 178 ms 140876 KB Output is correct
10 Correct 120 ms 140772 KB Output is correct
11 Correct 140 ms 140712 KB Output is correct
12 Correct 118 ms 140832 KB Output is correct
13 Correct 121 ms 140800 KB Output is correct
14 Correct 118 ms 140680 KB Output is correct
15 Correct 167 ms 140748 KB Output is correct
16 Correct 202 ms 140828 KB Output is correct
17 Correct 172 ms 140764 KB Output is correct
18 Correct 122 ms 140756 KB Output is correct
19 Correct 128 ms 140760 KB Output is correct
20 Correct 124 ms 140708 KB Output is correct
21 Correct 127 ms 140768 KB Output is correct
22 Correct 129 ms 140680 KB Output is correct
23 Correct 126 ms 140876 KB Output is correct
24 Correct 129 ms 140756 KB Output is correct
25 Correct 621 ms 139844 KB Output is correct

Subtask #3
0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 57 ms 139832 KB Output is correct
2 Correct 57 ms 139760 KB Output is correct
3 Correct 129 ms 148684 KB Output is correct
4 Correct 147 ms 148544 KB Output is correct
5 Correct 148 ms 148616 KB Output is correct
6 Correct 142 ms 148480 KB Output is correct
7 Correct 126 ms 148548 KB Output is correct
8 Correct 123 ms 148424 KB Output is correct
9 Correct 136 ms 148508 KB Output is correct
10 Correct 145 ms 148552 KB Output is correct
11 Correct 139 ms 148516 KB Output is correct
12 Correct 138 ms 147888 KB Output is correct
13 Correct 126 ms 148020 KB Output is correct
14 Correct 143 ms 147944 KB Output is correct
15 Correct 132 ms 148020 KB Output is correct
16 Correct 117 ms 147744 KB Output is correct
17 Correct 124 ms 147800 KB Output is correct
18 Correct 114 ms 147904 KB Output is correct
19 Correct 110 ms 147724 KB Output is correct
20 Correct 109 ms 147720 KB Output is correct
21 Correct 112 ms 147788 KB Output is correct
22 Correct 63 ms 139856 KB Output is correct
23 Correct 64 ms 139756 KB Output is correct
24 Correct 59 ms 139848 KB Output is correct
25 Correct 55 ms 139904 KB Output is correct
26 Correct 56 ms 139852 KB Output is correct
27 Correct 56 ms 139848 KB Output is correct
28 Correct 58 ms 139844 KB Output is correct
29 Correct 68 ms 139792 KB Output is correct
30 Correct 65 ms 139800 KB Output is correct
31 Correct 172 ms 140784 KB Output is correct
32 Correct 150 ms 140748 KB Output is correct
33 Correct 206 ms 140800 KB Output is correct
34 Correct 169 ms 140696 KB Output is correct
35 Correct 178 ms 140876 KB Output is correct
36 Correct 120 ms 140772 KB Output is correct
37 Correct 140 ms 140712 KB Output is correct
38 Correct 118 ms 140832 KB Output is correct
39 Correct 121 ms 140800 KB Output is correct
40 Correct 118 ms 140680 KB Output is correct
41 Correct 167 ms 140748 KB Output is correct
42 Correct 202 ms 140828 KB Output is correct
43 Correct 172 ms 140764 KB Output is correct
44 Correct 122 ms 140756 KB Output is correct
45 Correct 128 ms 140760 KB Output is correct
46 Correct 124 ms 140708 KB Output is correct
47 Correct 127 ms 140768 KB Output is correct
48 Correct 129 ms 140680 KB Output is correct
49 Correct 126 ms 140876 KB Output is correct
50 Correct 129 ms 140756 KB Output is correct
51 Correct 621 ms 139844 KB Output is correct
52 Correct 1866 ms 220500 KB Output is correct
53 Execution timed out 2083 ms 232312 KB Time limit exceeded
54 Halted 0 ms 0 KB -