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Submission #635430

# Submission time Handle Problem Language Result Execution time Memory
635430 2022-08-26T09:01:24 Z S2speed LOSTIKS (INOI20_lostiks) C++17
59 / 100
 2000 ms 250744 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];
int dis[22][maxn];
int bfs[maxn] , sz = 0;
int g[maxn] , k[22] , d[22] , e[22] , f[22][22] , dp[maxn][22] , ind[22];

void rBFS(int r , int h){
	sz = 0;
	dis[h][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[h][i] < dis[h][v] + 1) continue;
			g[i] = g[v];
			if(t != -1){
				g[i] ^= (1 << t);
				d[t] = v;
			}
			dis[h][i] = dis[h][v] + 1;
			bfs[sz++] = i;
		}
	}
	return;
}

void BFS(int r , int h){
	sz = 0;
	dis[h][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[h][i] < dis[h][v] + 1) continue;
			dis[h][i] = dis[h][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));
	memset(dis , 63 , sizeof(dis));
	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});
		}
	}
	rBFS(s , m);
	if(g[t] == 0){
		cout<<dis[m][t]<<'\n';
		return 0;
	}
	for(int j = 0 ; j < m ; j++){
		e[j] = g[k[j]] | g[d[j]];
		BFS(d[j] , j);
		if(e[j] == 0){
			dp[(1 << j)][j] = dis[m][k[j]] + dis[j][k[j]];
		}
	}
	for(int i = 0 ; i < m ; i++){
		for(int j = 0 ; j < m ; j++){
			f[i][j] = dis[i][k[j]] + dis[j][k[j]];
		}
	}
	int lm = (1 << m);
	for(int mask = 3 ; mask < lm ; mask++){
		int bp = 0;
		for(int j = 0 ; j < m ; j++){
			if(mask & (1 << j)) ind[bp++] = j;
		}
		if(bp == 1) continue;
		for(int jj = 0 ; jj < bp ; jj++){
			int j = ind[jj];
			if((e[j] & mask) != e[j]) continue;
			int h = inf , msk = mask ^ (1 << j);
			for(int ii = 0 ; ii < bp ; ii++){
				int i = ind[ii];
				if(i == j) continue;
				h = min(h , dp[msk][i] + f[i][j]);
			}
			dp[mask][j] = h;
		}
	}
	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[i][t]);
		}
		ans = min(ans , h);
	}
	cout<<(ans == inf ? -1 : ans)<<'\n';
	return 0;
}

Compilation message

Main.cpp: In function 'void BFS(int, int)':
Main.cpp:52:22: warning: unused variable 't' [-Wunused-variable]
   52 |    int i = p.first , t = p.second;
      |                      ^

Subtask #1
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 75 ms 205520 KB Output is correct
2 Correct 81 ms 205432 KB Output is correct
3 Correct 152 ms 210008 KB Output is correct
4 Correct 146 ms 210048 KB Output is correct
5 Correct 137 ms 210044 KB Output is correct
6 Correct 145 ms 210048 KB Output is correct
7 Correct 133 ms 210056 KB Output is correct
8 Correct 145 ms 209992 KB Output is correct
9 Correct 149 ms 210056 KB Output is correct
10 Correct 140 ms 209964 KB Output is correct
11 Correct 138 ms 209944 KB Output is correct
12 Correct 130 ms 209368 KB Output is correct
13 Correct 134 ms 209432 KB Output is correct
14 Correct 149 ms 209376 KB Output is correct
15 Correct 134 ms 209328 KB Output is correct
16 Correct 131 ms 209392 KB Output is correct
17 Correct 142 ms 209356 KB Output is correct
18 Correct 139 ms 209356 KB Output is correct
19 Correct 122 ms 209356 KB Output is correct
20 Correct 122 ms 209440 KB Output is correct
21 Correct 124 ms 209424 KB Output is correct
22 Correct 75 ms 205420 KB Output is correct
23 Correct 75 ms 205492 KB Output is correct
24 Correct 79 ms 205496 KB Output is correct
25 Correct 76 ms 205460 KB Output is correct
26 Correct 77 ms 205480 KB Output is correct

Subtask #2
36.0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 86 ms 205420 KB Output is correct
2 Correct 74 ms 205480 KB Output is correct
3 Correct 76 ms 205516 KB Output is correct
4 Correct 77 ms 205600 KB Output is correct
5 Correct 157 ms 205780 KB Output is correct
6 Correct 152 ms 205896 KB Output is correct
7 Correct 166 ms 205844 KB Output is correct
8 Correct 149 ms 205756 KB Output is correct
9 Correct 165 ms 205852 KB Output is correct
10 Correct 123 ms 205832 KB Output is correct
11 Correct 132 ms 205796 KB Output is correct
12 Correct 126 ms 205772 KB Output is correct
13 Correct 127 ms 205772 KB Output is correct
14 Correct 126 ms 205752 KB Output is correct
15 Correct 147 ms 205784 KB Output is correct
16 Correct 161 ms 205768 KB Output is correct
17 Correct 153 ms 205788 KB Output is correct
18 Correct 123 ms 205760 KB Output is correct
19 Correct 125 ms 205796 KB Output is correct
20 Correct 147 ms 205716 KB Output is correct
21 Correct 125 ms 205804 KB Output is correct
22 Correct 124 ms 205812 KB Output is correct
23 Correct 133 ms 205744 KB Output is correct
24 Correct 126 ms 205800 KB Output is correct
25 Correct 381 ms 205516 KB Output is correct

Subtask #3
0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 75 ms 205520 KB Output is correct
2 Correct 81 ms 205432 KB Output is correct
3 Correct 152 ms 210008 KB Output is correct
4 Correct 146 ms 210048 KB Output is correct
5 Correct 137 ms 210044 KB Output is correct
6 Correct 145 ms 210048 KB Output is correct
7 Correct 133 ms 210056 KB Output is correct
8 Correct 145 ms 209992 KB Output is correct
9 Correct 149 ms 210056 KB Output is correct
10 Correct 140 ms 209964 KB Output is correct
11 Correct 138 ms 209944 KB Output is correct
12 Correct 130 ms 209368 KB Output is correct
13 Correct 134 ms 209432 KB Output is correct
14 Correct 149 ms 209376 KB Output is correct
15 Correct 134 ms 209328 KB Output is correct
16 Correct 131 ms 209392 KB Output is correct
17 Correct 142 ms 209356 KB Output is correct
18 Correct 139 ms 209356 KB Output is correct
19 Correct 122 ms 209356 KB Output is correct
20 Correct 122 ms 209440 KB Output is correct
21 Correct 124 ms 209424 KB Output is correct
22 Correct 75 ms 205420 KB Output is correct
23 Correct 75 ms 205492 KB Output is correct
24 Correct 79 ms 205496 KB Output is correct
25 Correct 76 ms 205460 KB Output is correct
26 Correct 77 ms 205480 KB Output is correct
27 Correct 86 ms 205420 KB Output is correct
28 Correct 74 ms 205480 KB Output is correct
29 Correct 76 ms 205516 KB Output is correct
30 Correct 77 ms 205600 KB Output is correct
31 Correct 157 ms 205780 KB Output is correct
32 Correct 152 ms 205896 KB Output is correct
33 Correct 166 ms 205844 KB Output is correct
34 Correct 149 ms 205756 KB Output is correct
35 Correct 165 ms 205852 KB Output is correct
36 Correct 123 ms 205832 KB Output is correct
37 Correct 132 ms 205796 KB Output is correct
38 Correct 126 ms 205772 KB Output is correct
39 Correct 127 ms 205772 KB Output is correct
40 Correct 126 ms 205752 KB Output is correct
41 Correct 147 ms 205784 KB Output is correct
42 Correct 161 ms 205768 KB Output is correct
43 Correct 153 ms 205788 KB Output is correct
44 Correct 123 ms 205760 KB Output is correct
45 Correct 125 ms 205796 KB Output is correct
46 Correct 147 ms 205716 KB Output is correct
47 Correct 125 ms 205804 KB Output is correct
48 Correct 124 ms 205812 KB Output is correct
49 Correct 133 ms 205744 KB Output is correct
50 Correct 126 ms 205800 KB Output is correct
51 Correct 381 ms 205516 KB Output is correct
52 Correct 1855 ms 250744 KB Output is correct
53 Execution timed out 2098 ms 250628 KB Time limit exceeded
54 Halted 0 ms 0 KB -