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Submission #635326

# Submission time Handle Problem Language Result Execution time Memory
635326 2022-08-26T05:24:13 Z S2speed LOSTIKS (INOI20_lostiks) C++17
59 / 100
 2000 ms 232008 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];
int bfs[maxn] , sz = 0;
int g[maxn] , k[22] , d[22] , e[22] , dp[maxn][22];

void BFS(int r , bool f = false){
	sz = 0;
	dis[r].assign(n , inf);
	dis[r][r] = 0;
	g[r] = 0;
	bfs[sz++] = r;
	int x = 0;
	while(x < sz){
		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[sz++] = 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 68 ms 139792 KB Output is correct
2 Correct 64 ms 139848 KB Output is correct
3 Correct 125 ms 147464 KB Output is correct
4 Correct 126 ms 147532 KB Output is correct
5 Correct 140 ms 147536 KB Output is correct
6 Correct 131 ms 147484 KB Output is correct
7 Correct 142 ms 147520 KB Output is correct
8 Correct 142 ms 147492 KB Output is correct
9 Correct 121 ms 147424 KB Output is correct
10 Correct 129 ms 147432 KB Output is correct
11 Correct 143 ms 147420 KB Output is correct
12 Correct 144 ms 146924 KB Output is correct
13 Correct 119 ms 146880 KB Output is correct
14 Correct 136 ms 146920 KB Output is correct
15 Correct 123 ms 146892 KB Output is correct
16 Correct 131 ms 146816 KB Output is correct
17 Correct 145 ms 146832 KB Output is correct
18 Correct 114 ms 146912 KB Output is correct
19 Correct 121 ms 146924 KB Output is correct
20 Correct 116 ms 146888 KB Output is correct
21 Correct 126 ms 146828 KB Output is correct
22 Correct 58 ms 139736 KB Output is correct
23 Correct 57 ms 139792 KB Output is correct
24 Correct 60 ms 139788 KB Output is correct
25 Correct 56 ms 139852 KB Output is correct
26 Correct 68 ms 139748 KB Output is correct

Subtask #2
36.0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 58 ms 139760 KB Output is correct
2 Correct 58 ms 139812 KB Output is correct
3 Correct 69 ms 139848 KB Output is correct
4 Correct 66 ms 139872 KB Output is correct
5 Correct 183 ms 140716 KB Output is correct
6 Correct 172 ms 140736 KB Output is correct
7 Correct 245 ms 140724 KB Output is correct
8 Correct 162 ms 140600 KB Output is correct
9 Correct 180 ms 140832 KB Output is correct
10 Correct 138 ms 140760 KB Output is correct
11 Correct 144 ms 140692 KB Output is correct
12 Correct 123 ms 140628 KB Output is correct
13 Correct 148 ms 140720 KB Output is correct
14 Correct 144 ms 140716 KB Output is correct
15 Correct 164 ms 140684 KB Output is correct
16 Correct 189 ms 140740 KB Output is correct
17 Correct 175 ms 140680 KB Output is correct
18 Correct 127 ms 140680 KB Output is correct
19 Correct 148 ms 140592 KB Output is correct
20 Correct 125 ms 140796 KB Output is correct
21 Correct 147 ms 140684 KB Output is correct
22 Correct 154 ms 140584 KB Output is correct
23 Correct 121 ms 140644 KB Output is correct
24 Correct 140 ms 140676 KB Output is correct
25 Correct 625 ms 139848 KB Output is correct

Subtask #3
0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 68 ms 139792 KB Output is correct
2 Correct 64 ms 139848 KB Output is correct
3 Correct 125 ms 147464 KB Output is correct
4 Correct 126 ms 147532 KB Output is correct
5 Correct 140 ms 147536 KB Output is correct
6 Correct 131 ms 147484 KB Output is correct
7 Correct 142 ms 147520 KB Output is correct
8 Correct 142 ms 147492 KB Output is correct
9 Correct 121 ms 147424 KB Output is correct
10 Correct 129 ms 147432 KB Output is correct
11 Correct 143 ms 147420 KB Output is correct
12 Correct 144 ms 146924 KB Output is correct
13 Correct 119 ms 146880 KB Output is correct
14 Correct 136 ms 146920 KB Output is correct
15 Correct 123 ms 146892 KB Output is correct
16 Correct 131 ms 146816 KB Output is correct
17 Correct 145 ms 146832 KB Output is correct
18 Correct 114 ms 146912 KB Output is correct
19 Correct 121 ms 146924 KB Output is correct
20 Correct 116 ms 146888 KB Output is correct
21 Correct 126 ms 146828 KB Output is correct
22 Correct 58 ms 139736 KB Output is correct
23 Correct 57 ms 139792 KB Output is correct
24 Correct 60 ms 139788 KB Output is correct
25 Correct 56 ms 139852 KB Output is correct
26 Correct 68 ms 139748 KB Output is correct
27 Correct 58 ms 139760 KB Output is correct
28 Correct 58 ms 139812 KB Output is correct
29 Correct 69 ms 139848 KB Output is correct
30 Correct 66 ms 139872 KB Output is correct
31 Correct 183 ms 140716 KB Output is correct
32 Correct 172 ms 140736 KB Output is correct
33 Correct 245 ms 140724 KB Output is correct
34 Correct 162 ms 140600 KB Output is correct
35 Correct 180 ms 140832 KB Output is correct
36 Correct 138 ms 140760 KB Output is correct
37 Correct 144 ms 140692 KB Output is correct
38 Correct 123 ms 140628 KB Output is correct
39 Correct 148 ms 140720 KB Output is correct
40 Correct 144 ms 140716 KB Output is correct
41 Correct 164 ms 140684 KB Output is correct
42 Correct 189 ms 140740 KB Output is correct
43 Correct 175 ms 140680 KB Output is correct
44 Correct 127 ms 140680 KB Output is correct
45 Correct 148 ms 140592 KB Output is correct
46 Correct 125 ms 140796 KB Output is correct
47 Correct 147 ms 140684 KB Output is correct
48 Correct 154 ms 140584 KB Output is correct
49 Correct 121 ms 140644 KB Output is correct
50 Correct 140 ms 140676 KB Output is correct
51 Correct 625 ms 139848 KB Output is correct
52 Correct 1928 ms 220368 KB Output is correct
53 Execution timed out 2073 ms 232008 KB Time limit exceeded
54 Halted 0 ms 0 KB -