#include <bits/stdc++.h>
//#pragma GCC optimize ("Ofast,unroll-loops")
//#pragma GCC target ("avx2")
using namespace std;
typedef long long ll;
typedef pair<int, int> pp;
#define rep(i,l,r) for(int i = (l); i < (r); i++)
#define per(i,r,l) for(int i = (r); i >= (l); i--)
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
#define pb push_back
#define ff first
#define ss second
void dbg(){
cerr << endl;
}
template<typename Head, typename... Tail> void dbg(Head h, Tail... t){
cerr << " " << h << ",";
dbg(t...);
}
#define er(...) cerr << __LINE__ << " <" << #__VA_ARGS__ << ">:", dbg(__VA_ARGS__)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
void IOS(){
cin.tie(0) -> sync_with_stdio(0);
// #ifndef ONLINE_JUDGE
// freopen("inp.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
// #endif
}
const ll mod = 1e9 + 7, maxn = 1e6 + 5, maxm = 20, inf = ll(1e9) + 5;
int val[maxn], ed[maxm], nxt[maxm], tmp, n;
vector<pp> adj[maxn];
void dfs(int r, int p){
val[r] |= val[p];
for(auto&[c, w]: adj[r]) if(c - p){
if(w + 1){
ed[tmp] = r;
nxt[tmp] = w;
val[c] = 1<<tmp;
tmp++;
dfs(c, r);
} else{
dfs(c, r);
}
}
}
int dist[maxm + 1][maxn], dq[maxn], st, en, tmp_vl[maxm][maxm];
void dfs2(int r, int id){
// vector<pp> stk;
// for(auto&[c, w]: adj[r]) if(c - p){
// dist[id][c] = dist[id][r] + 1;
// dfs2(c, r);
// }
dq[st = 0] = r, en = 1;
fill(dist[id], dist[id] + n, -1);
dist[id][r] = 0;
while(st < en){
int r = dq[st++];
for(auto&[c, w]: adj[r]) if(dist[id][c] == -1){
dist[id][c] = dist[id][r] + 1;
dq[en++] = c;
}
}
}
int dp[1<<maxm][maxm];
int main(){ IOS();
int s, t; cin >> n >> s >> t; s--, t--;
int m = 0;
rep(i,1,n){
int u, v, w; cin >> u >> v >> w; u--, v--, w--;
adj[u].pb({v, w});
adj[v].pb({u, w});
m += w != -1;
}
dfs(s, -1);
rep(i,0,m){
dfs2(ed[i], i);
}
dfs2(s, m);
rep(i,0,m){
rep(j,0,m){
tmp_vl[i][j] = dist[i][nxt[j]] + dist[j][nxt[j]];
}
}
auto chk = [&](int msk, int r){
return (val[r]&msk) == val[r];
};
vector<int> is(m), nis(m);
int ptr_is = 0, ptr_nis = 0;
per(i,(1<<m)-1,1){
ptr_is = ptr_nis = 0;
rep(e,0,m) {
if(i>>e&1){
if(chk(i, ed[e])) is[ptr_is++] = e;
}else{
if(chk(i, nxt[e]) && chk(i, ed[e])) nis[ptr_nis++] = e;
}
}
rep(x,0,ptr_is){
int e = is[x];
dp[i][e] = inf;
if(chk(i, t)){
dp[i][e] = dist[e][t];
}else{
rep(j,0,ptr_nis){
int x = nis[j];
dp[i][e] = min(dp[i][e], dp[i^(1<<x)][x] + tmp_vl[e][x]);
}
}
}
}
int ans = inf;
rep(i,0,m){
if(chk(0, nxt[i]) && chk(0, ed[i])) ans = min(ans, dp[1<<i][i] + dist[m][nxt[i]] + dist[i][nxt[i]]);
}
if(chk(0, t)){
ans = dist[m][t];
}
cout << (ans == inf? -1: ans) << '\n';
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
13 ms |
23764 KB |
Output is correct |
2 |
Correct |
13 ms |
23820 KB |
Output is correct |
3 |
Correct |
81 ms |
31820 KB |
Output is correct |
4 |
Correct |
83 ms |
31868 KB |
Output is correct |
5 |
Correct |
87 ms |
31884 KB |
Output is correct |
6 |
Correct |
98 ms |
31860 KB |
Output is correct |
7 |
Correct |
79 ms |
31988 KB |
Output is correct |
8 |
Correct |
87 ms |
31916 KB |
Output is correct |
9 |
Correct |
89 ms |
32076 KB |
Output is correct |
10 |
Correct |
89 ms |
31976 KB |
Output is correct |
11 |
Correct |
76 ms |
31992 KB |
Output is correct |
12 |
Correct |
77 ms |
32880 KB |
Output is correct |
13 |
Correct |
77 ms |
32612 KB |
Output is correct |
14 |
Correct |
75 ms |
32344 KB |
Output is correct |
15 |
Correct |
81 ms |
33132 KB |
Output is correct |
16 |
Correct |
78 ms |
33640 KB |
Output is correct |
17 |
Correct |
90 ms |
33704 KB |
Output is correct |
18 |
Correct |
87 ms |
34096 KB |
Output is correct |
19 |
Correct |
74 ms |
37300 KB |
Output is correct |
20 |
Correct |
77 ms |
37288 KB |
Output is correct |
21 |
Correct |
85 ms |
36952 KB |
Output is correct |
22 |
Correct |
14 ms |
23772 KB |
Output is correct |
23 |
Correct |
12 ms |
23892 KB |
Output is correct |
24 |
Correct |
14 ms |
23876 KB |
Output is correct |
25 |
Correct |
13 ms |
23892 KB |
Output is correct |
26 |
Correct |
13 ms |
23824 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
11 ms |
23856 KB |
Output is correct |
3 |
Correct |
13 ms |
23936 KB |
Output is correct |
4 |
Correct |
13 ms |
23996 KB |
Output is correct |
5 |
Correct |
112 ms |
65828 KB |
Output is correct |
6 |
Correct |
87 ms |
65868 KB |
Output is correct |
7 |
Correct |
97 ms |
65904 KB |
Output is correct |
8 |
Correct |
92 ms |
65868 KB |
Output is correct |
9 |
Correct |
97 ms |
65872 KB |
Output is correct |
10 |
Correct |
78 ms |
65896 KB |
Output is correct |
11 |
Correct |
73 ms |
65864 KB |
Output is correct |
12 |
Correct |
75 ms |
65964 KB |
Output is correct |
13 |
Correct |
73 ms |
65936 KB |
Output is correct |
14 |
Correct |
72 ms |
65868 KB |
Output is correct |
15 |
Correct |
93 ms |
65852 KB |
Output is correct |
16 |
Correct |
97 ms |
65868 KB |
Output is correct |
17 |
Correct |
93 ms |
65880 KB |
Output is correct |
18 |
Correct |
72 ms |
66008 KB |
Output is correct |
19 |
Correct |
75 ms |
66004 KB |
Output is correct |
20 |
Correct |
77 ms |
65996 KB |
Output is correct |
21 |
Correct |
69 ms |
66044 KB |
Output is correct |
22 |
Correct |
70 ms |
66336 KB |
Output is correct |
23 |
Correct |
76 ms |
66304 KB |
Output is correct |
24 |
Correct |
77 ms |
66296 KB |
Output is correct |
25 |
Correct |
264 ms |
106012 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
13 ms |
23764 KB |
Output is correct |
2 |
Correct |
13 ms |
23820 KB |
Output is correct |
3 |
Correct |
81 ms |
31820 KB |
Output is correct |
4 |
Correct |
83 ms |
31868 KB |
Output is correct |
5 |
Correct |
87 ms |
31884 KB |
Output is correct |
6 |
Correct |
98 ms |
31860 KB |
Output is correct |
7 |
Correct |
79 ms |
31988 KB |
Output is correct |
8 |
Correct |
87 ms |
31916 KB |
Output is correct |
9 |
Correct |
89 ms |
32076 KB |
Output is correct |
10 |
Correct |
89 ms |
31976 KB |
Output is correct |
11 |
Correct |
76 ms |
31992 KB |
Output is correct |
12 |
Correct |
77 ms |
32880 KB |
Output is correct |
13 |
Correct |
77 ms |
32612 KB |
Output is correct |
14 |
Correct |
75 ms |
32344 KB |
Output is correct |
15 |
Correct |
81 ms |
33132 KB |
Output is correct |
16 |
Correct |
78 ms |
33640 KB |
Output is correct |
17 |
Correct |
90 ms |
33704 KB |
Output is correct |
18 |
Correct |
87 ms |
34096 KB |
Output is correct |
19 |
Correct |
74 ms |
37300 KB |
Output is correct |
20 |
Correct |
77 ms |
37288 KB |
Output is correct |
21 |
Correct |
85 ms |
36952 KB |
Output is correct |
22 |
Correct |
14 ms |
23772 KB |
Output is correct |
23 |
Correct |
12 ms |
23892 KB |
Output is correct |
24 |
Correct |
14 ms |
23876 KB |
Output is correct |
25 |
Correct |
13 ms |
23892 KB |
Output is correct |
26 |
Correct |
13 ms |
23824 KB |
Output is correct |
27 |
Correct |
12 ms |
23764 KB |
Output is correct |
28 |
Correct |
11 ms |
23856 KB |
Output is correct |
29 |
Correct |
13 ms |
23936 KB |
Output is correct |
30 |
Correct |
13 ms |
23996 KB |
Output is correct |
31 |
Correct |
112 ms |
65828 KB |
Output is correct |
32 |
Correct |
87 ms |
65868 KB |
Output is correct |
33 |
Correct |
97 ms |
65904 KB |
Output is correct |
34 |
Correct |
92 ms |
65868 KB |
Output is correct |
35 |
Correct |
97 ms |
65872 KB |
Output is correct |
36 |
Correct |
78 ms |
65896 KB |
Output is correct |
37 |
Correct |
73 ms |
65864 KB |
Output is correct |
38 |
Correct |
75 ms |
65964 KB |
Output is correct |
39 |
Correct |
73 ms |
65936 KB |
Output is correct |
40 |
Correct |
72 ms |
65868 KB |
Output is correct |
41 |
Correct |
93 ms |
65852 KB |
Output is correct |
42 |
Correct |
97 ms |
65868 KB |
Output is correct |
43 |
Correct |
93 ms |
65880 KB |
Output is correct |
44 |
Correct |
72 ms |
66008 KB |
Output is correct |
45 |
Correct |
75 ms |
66004 KB |
Output is correct |
46 |
Correct |
77 ms |
65996 KB |
Output is correct |
47 |
Correct |
69 ms |
66044 KB |
Output is correct |
48 |
Correct |
70 ms |
66336 KB |
Output is correct |
49 |
Correct |
76 ms |
66304 KB |
Output is correct |
50 |
Correct |
77 ms |
66296 KB |
Output is correct |
51 |
Correct |
264 ms |
106012 KB |
Output is correct |
52 |
Execution timed out |
2013 ms |
109432 KB |
Time limit exceeded |
53 |
Halted |
0 ms |
0 KB |
- |