// In the name of the God
#include <bits/stdc++.h>
#define ll long long
#define int long long
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define pii pair <int, int>
#define smin(x, y) (x) = min((x), (y))
#define smax(x, y) (x) = max((x), (y))
#define all(x) (x).begin(), (x).end()
using namespace std;
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2")
const int inf = 1e9+7;
const int mod = 998244353;
const int maxn = 1e6+5, lg = 22;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int n, m, s, t, ti = 0, h[maxn], in[maxn], out[maxn], par[maxn][lg], dist[lg][lg], ne[lg][lg], dp[1<<lg][lg];
vector <int> adj[maxn];
vector <pair <pii, int>> g;
void dfs(int v, int p) {
par[v][0] = p;
for (int i = 1; i < lg; i++) par[v][i] = par[par[v][i-1]][i-1];
in[v] = ti++;
for (int u : adj[v]) {
if (u == p) continue;
h[u] = h[v]+1;
dfs(u, v);
}
out[v] = ti;
}
int lca(int v, int u) {
if (h[v] < h[u]) swap(v, u);
int x = h[v]-h[u];
for (int i = 0; i < lg; i++) {
if (x&(1<<i)) v = par[v][i];
}
if (v == u) return v;
for (int i = lg-1; i >= 0; i--) {
if (par[v][i] != par[u][i]) v = par[v][i], u = par[u][i];
}
return par[v][0];
}
int d(int v, int u) {
int z = lca(u, v);
return h[v]+h[u]-h[z]*2;
}
bool isd(int v, int u) {
return in[v] <= in[u] and out[v] >= out[u];
}
int f(int v, int u) {
int res = 0, z = lca(u, v);
for (int i = 0; i < m; i++) {
int x = g[i].F.F, y = g[i].F.S;
bool f = 0;
f = (isd(y, v)&isd(z, x))|(isd(y, u)&isd(z, x));
if (f) res += 1<<i;
}
return res;
}
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> s >> t; s--, t--;
for (int i = 1; i < n; i++) {
int v, u, w; cin >> v >> u >> w; v--, u--, w--;
adj[v].pb(u), adj[u].pb(v);
if (w != -1) g.pb(mp(mp(v, u), w));
}
m = g.size();
dfs(s, s);
for (auto &p : g) if (h[p.F.F] > h[p.F.S]) swap(p.F.F, p.F.S);
for (int i = 0; i < m; i++) {
for (int j = 0; j < m; j++) {
dist[i][j] = d(g[i].F.F, g[j].S);
ne[i][j] = f(g[i].F.F, g[j].S);
}
}
for (int i = 0; i < (1<<m); i++) {
for (int j = 0; j < m; j++) dp[i][j] = inf*inf;
}
for (int i = 0; i < m; i++) {
if (f(s, g[i].S) == 0 and f(g[i].S , g[i].F.F) == 0) dp[1<<i][i] = d(s, g[i].S)+d(g[i].S, g[i].F.F);
}
for (int i = 0; i < (1<<m); i++) {
for (int j = 0; j < m; j++) {
if (i&(1<<j)) {
for (int k = 0; k < m; k++) {
if (!(i&(1<<k))) {
if ((ne[j][k]|i) == i and (ne[k][k]|i) == i) smin(dp[i+(1<<k)][k], dp[i][j]+dist[j][k]+dist[k][k]);
}
}
}
}
}
if (s == t) return cout << 0 << '\n', 0;
int ali = -1, p = t;
while (p != s) {
for (int i = 0; i < m; i++) {
if (g[i].F.S == p) {
ali = i;
goto TH;
}
}
p = par[p][0];
}
TH:;
if (ali == -1) return cout << d(s, t) << '\n', 0;
int amir = d(g[ali].F.F, t), ans = inf*inf;
for (int i = 0; i < (1<<m); i++) smin(ans, amir+dp[i][ali]);
cout << (ans == inf*inf ? -1 : ans) << '\n';
return 0;
}
/*
srand(time(0));
cout << (rand()%1900) + 1 << ' ' << (rand()%2)+5 << '\n';
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
31324 KB |
Output is correct |
2 |
Correct |
5 ms |
31324 KB |
Output is correct |
3 |
Correct |
40 ms |
53876 KB |
Output is correct |
4 |
Correct |
41 ms |
54104 KB |
Output is correct |
5 |
Correct |
43 ms |
54100 KB |
Output is correct |
6 |
Correct |
46 ms |
54096 KB |
Output is correct |
7 |
Correct |
51 ms |
54352 KB |
Output is correct |
8 |
Correct |
43 ms |
54356 KB |
Output is correct |
9 |
Correct |
45 ms |
54452 KB |
Output is correct |
10 |
Correct |
41 ms |
54352 KB |
Output is correct |
11 |
Correct |
43 ms |
54352 KB |
Output is correct |
12 |
Correct |
48 ms |
54964 KB |
Output is correct |
13 |
Correct |
41 ms |
54100 KB |
Output is correct |
14 |
Correct |
40 ms |
53840 KB |
Output is correct |
15 |
Correct |
43 ms |
54864 KB |
Output is correct |
16 |
Correct |
43 ms |
55376 KB |
Output is correct |
17 |
Correct |
43 ms |
55388 KB |
Output is correct |
18 |
Correct |
52 ms |
55636 KB |
Output is correct |
19 |
Correct |
44 ms |
58204 KB |
Output is correct |
20 |
Correct |
46 ms |
57932 KB |
Output is correct |
21 |
Correct |
44 ms |
57940 KB |
Output is correct |
22 |
Correct |
5 ms |
31320 KB |
Output is correct |
23 |
Correct |
5 ms |
31324 KB |
Output is correct |
24 |
Correct |
5 ms |
31324 KB |
Output is correct |
25 |
Correct |
5 ms |
31324 KB |
Output is correct |
26 |
Correct |
5 ms |
31320 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
31332 KB |
Output is correct |
2 |
Correct |
5 ms |
31376 KB |
Output is correct |
3 |
Correct |
5 ms |
31324 KB |
Output is correct |
4 |
Correct |
5 ms |
31320 KB |
Output is correct |
5 |
Correct |
350 ms |
121948 KB |
Output is correct |
6 |
Correct |
343 ms |
122016 KB |
Output is correct |
7 |
Correct |
341 ms |
122020 KB |
Output is correct |
8 |
Correct |
339 ms |
121868 KB |
Output is correct |
9 |
Correct |
338 ms |
121944 KB |
Output is correct |
10 |
Correct |
335 ms |
121948 KB |
Output is correct |
11 |
Correct |
343 ms |
121944 KB |
Output is correct |
12 |
Correct |
332 ms |
121988 KB |
Output is correct |
13 |
Correct |
334 ms |
121948 KB |
Output is correct |
14 |
Correct |
326 ms |
121948 KB |
Output is correct |
15 |
Correct |
343 ms |
122000 KB |
Output is correct |
16 |
Correct |
335 ms |
121944 KB |
Output is correct |
17 |
Correct |
346 ms |
121948 KB |
Output is correct |
18 |
Correct |
323 ms |
121948 KB |
Output is correct |
19 |
Correct |
320 ms |
121948 KB |
Output is correct |
20 |
Correct |
318 ms |
122092 KB |
Output is correct |
21 |
Correct |
304 ms |
122116 KB |
Output is correct |
22 |
Correct |
322 ms |
122184 KB |
Output is correct |
23 |
Correct |
291 ms |
122192 KB |
Output is correct |
24 |
Correct |
324 ms |
122296 KB |
Output is correct |
25 |
Correct |
685 ms |
210512 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
31324 KB |
Output is correct |
2 |
Correct |
5 ms |
31324 KB |
Output is correct |
3 |
Correct |
40 ms |
53876 KB |
Output is correct |
4 |
Correct |
41 ms |
54104 KB |
Output is correct |
5 |
Correct |
43 ms |
54100 KB |
Output is correct |
6 |
Correct |
46 ms |
54096 KB |
Output is correct |
7 |
Correct |
51 ms |
54352 KB |
Output is correct |
8 |
Correct |
43 ms |
54356 KB |
Output is correct |
9 |
Correct |
45 ms |
54452 KB |
Output is correct |
10 |
Correct |
41 ms |
54352 KB |
Output is correct |
11 |
Correct |
43 ms |
54352 KB |
Output is correct |
12 |
Correct |
48 ms |
54964 KB |
Output is correct |
13 |
Correct |
41 ms |
54100 KB |
Output is correct |
14 |
Correct |
40 ms |
53840 KB |
Output is correct |
15 |
Correct |
43 ms |
54864 KB |
Output is correct |
16 |
Correct |
43 ms |
55376 KB |
Output is correct |
17 |
Correct |
43 ms |
55388 KB |
Output is correct |
18 |
Correct |
52 ms |
55636 KB |
Output is correct |
19 |
Correct |
44 ms |
58204 KB |
Output is correct |
20 |
Correct |
46 ms |
57932 KB |
Output is correct |
21 |
Correct |
44 ms |
57940 KB |
Output is correct |
22 |
Correct |
5 ms |
31320 KB |
Output is correct |
23 |
Correct |
5 ms |
31324 KB |
Output is correct |
24 |
Correct |
5 ms |
31324 KB |
Output is correct |
25 |
Correct |
5 ms |
31324 KB |
Output is correct |
26 |
Correct |
5 ms |
31320 KB |
Output is correct |
27 |
Correct |
5 ms |
31332 KB |
Output is correct |
28 |
Correct |
5 ms |
31376 KB |
Output is correct |
29 |
Correct |
5 ms |
31324 KB |
Output is correct |
30 |
Correct |
5 ms |
31320 KB |
Output is correct |
31 |
Correct |
350 ms |
121948 KB |
Output is correct |
32 |
Correct |
343 ms |
122016 KB |
Output is correct |
33 |
Correct |
341 ms |
122020 KB |
Output is correct |
34 |
Correct |
339 ms |
121868 KB |
Output is correct |
35 |
Correct |
338 ms |
121944 KB |
Output is correct |
36 |
Correct |
335 ms |
121948 KB |
Output is correct |
37 |
Correct |
343 ms |
121944 KB |
Output is correct |
38 |
Correct |
332 ms |
121988 KB |
Output is correct |
39 |
Correct |
334 ms |
121948 KB |
Output is correct |
40 |
Correct |
326 ms |
121948 KB |
Output is correct |
41 |
Correct |
343 ms |
122000 KB |
Output is correct |
42 |
Correct |
335 ms |
121944 KB |
Output is correct |
43 |
Correct |
346 ms |
121948 KB |
Output is correct |
44 |
Correct |
323 ms |
121948 KB |
Output is correct |
45 |
Correct |
320 ms |
121948 KB |
Output is correct |
46 |
Correct |
318 ms |
122092 KB |
Output is correct |
47 |
Correct |
304 ms |
122116 KB |
Output is correct |
48 |
Correct |
322 ms |
122184 KB |
Output is correct |
49 |
Correct |
291 ms |
122192 KB |
Output is correct |
50 |
Correct |
324 ms |
122296 KB |
Output is correct |
51 |
Correct |
685 ms |
210512 KB |
Output is correct |
52 |
Correct |
821 ms |
277976 KB |
Output is correct |
53 |
Correct |
857 ms |
277076 KB |
Output is correct |
54 |
Correct |
806 ms |
276304 KB |
Output is correct |
55 |
Correct |
819 ms |
276128 KB |
Output is correct |
56 |
Correct |
810 ms |
276048 KB |
Output is correct |
57 |
Correct |
830 ms |
277872 KB |
Output is correct |
58 |
Correct |
5 ms |
31320 KB |
Output is correct |
59 |
Correct |
5 ms |
31324 KB |
Output is correct |
60 |
Correct |
5 ms |
31344 KB |
Output is correct |
61 |
Correct |
806 ms |
277948 KB |
Output is correct |
62 |
Correct |
853 ms |
297296 KB |
Output is correct |
63 |
Correct |
812 ms |
286124 KB |
Output is correct |
64 |
Correct |
52 ms |
56788 KB |
Output is correct |
65 |
Correct |
55 ms |
56916 KB |
Output is correct |
66 |
Correct |
814 ms |
278096 KB |
Output is correct |
67 |
Correct |
800 ms |
277072 KB |
Output is correct |
68 |
Correct |
958 ms |
364128 KB |
Output is correct |
69 |
Correct |
958 ms |
363952 KB |
Output is correct |
70 |
Correct |
978 ms |
364112 KB |
Output is correct |
71 |
Correct |
953 ms |
363856 KB |
Output is correct |
72 |
Correct |
976 ms |
363840 KB |
Output is correct |
73 |
Correct |
979 ms |
364880 KB |
Output is correct |
74 |
Correct |
990 ms |
365652 KB |
Output is correct |
75 |
Correct |
982 ms |
364624 KB |
Output is correct |
76 |
Correct |
966 ms |
365724 KB |
Output is correct |
77 |
Correct |
918 ms |
364956 KB |
Output is correct |
78 |
Correct |
942 ms |
364192 KB |
Output is correct |
79 |
Correct |
985 ms |
363940 KB |
Output is correct |
80 |
Correct |
1006 ms |
362316 KB |
Output is correct |
81 |
Correct |
1051 ms |
372164 KB |
Output is correct |
82 |
Correct |
1077 ms |
373804 KB |
Output is correct |
83 |
Correct |
1031 ms |
373864 KB |
Output is correct |
84 |
Correct |
995 ms |
380500 KB |
Output is correct |
85 |
Correct |
1071 ms |
403332 KB |
Output is correct |
86 |
Correct |
1130 ms |
402512 KB |
Output is correct |
87 |
Correct |
1111 ms |
402680 KB |
Output is correct |