#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int mod = 1000 * 1000 * 1000 + 7;
const int INF = 1e9 + 100;
const ll LINF = 1e18 + 100;
#ifdef DEBUG
#define dbg(x) cout << #x << " = " << (x) << endl << flush;
#define dbgr(s, f) { cout << #s << ": "; for (auto _ = (s); _ != (f); _++) cout << *_ << ' '; cout << endl << flush; }
#else
#define dbg(x) ;
#define dbgr(s, f) ;
#endif
#define fast_io ios::sync_with_stdio(0); cin.tie(0);
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define fr first
#define sc second
#define endl '\n'
const int MAXN = 1000100;
const int MAXE = 22;
const int LOGN = 25;
int n, s, t, m;
int ef[MAXN], eto[MAXN], ky[MAXN], kind[MAXN];
vector<int> adj[MAXN];
int lpar[LOGN][MAXN];
int h[MAXN];
int pth[MAXN];
int lck[MAXE];
int dp[1 << 20][MAXE];
int inp[MAXE];
int cost[MAXE][MAXE];
int tot;
void dfs(int v)
{
for (int e : adj[v])
{
int u = ef[e] ^ eto[e] ^ v;
if (u == lpar[0][v]) continue;
lpar[0][u] = v;
h[u] = h[v] + 1;
pth[u] = pth[v] | (ky[e] ? (1 << kind[e]) : 0);
dfs(u);
}
}
void bkdfs(int v)
{
tot |= (1 << v);
FOR(i, 0, m) if ((inp[v] >> i & 1) && !(tot >> i & 1)) bkdfs(i);
}
inline int getpar(int x, int d)
{
FOR(i, 0, LOGN) if (d >> i & 1) x = lpar[i][x];
return x;
}
inline int getlca(int x, int y)
{
if (h[x] > h[y]) swap(x, y);
y = getpar(y, h[y] - h[x]);
if (x == y) return x;
for (int i = LOGN - 1; i >= 0; i--)
{
if (lpar[i][x] != lpar[i][y])
{
x = lpar[i][x];
y = lpar[i][y];
}
}
return lpar[0][x];
}
int32_t main(void)
{
fast_io;
cin >> n >> s >> t;
FOR(i, 0, n - 1)
{
cin >> ef[i] >> eto[i] >> ky[i];
adj[ef[i]].pb(i);
adj[eto[i]].pb(i);
if (ky[i])
{
lck[m] = i;
kind[i] = m;
m++;
}
}
dbg(m);
dfs(s);
dbgr(pth + 1, pth + n + 1);
if (pth[t] == 0)
{
return cout << h[t] << endl, 0;
}
FOR(i, 0, n - 1) if (h[ef[i]] > h[eto[i]]) swap(ef[i], eto[i]);
FOR(i, 1, LOGN) FOR(j, 1, n + 1) lpar[i][j] = lpar[i - 1][lpar[i - 1][j]];
FOR(i, 0, m)
{
int e = lck[i];
inp[i] = (pth[ef[e]] | pth[ky[e]]);
}
FOR(i, 0, m) FOR(j, 0, m) if (i != j)
{
int x = ef[lck[i]];
int y = ky[lck[j]];
int z = ef[lck[j]];
cost[i][j] = h[x] + h[y] - 2 * h[getlca(x, y)] + h[y] + h[z] - 2 * h[getlca(y, z)];
// cout << i << ' ' << j << ' ' << cost[i][j] << endl;
}
dbgr(h + 1, h + n + 1);
dbgr(pth + 1, pth + n + 1);
dbgr(lck, lck + m);
dbgr(inp, inp + m);
FOR(mask, 1, 1 << m) fill(dp[mask], dp[mask] + MAXE, INF);
FOR(mask, 1, 1 << m)
{
if (__builtin_popcount(mask) == 1)
{
int v = __lg(mask);
if (!(inp[v] & mask)) dp[mask][v] = 0;
continue;
}
FOR(v, 0, m)
{
if ((mask >> v & 1) && (inp[v] & mask) == 0)
{
int sub = mask ^ (1 << v);
FOR(x, 0, m) if (sub >> x & 1)
{
dp[mask][v] = min(dp[mask][v], dp[sub][x] + cost[v][x]);
}
}
}
}
// FOR(mask, 0, 1 << m) FOR(v, 0, m) cout << v << ' ' << mask << ' ' << dp[mask][v] << endl;
int laste = -1;
FOR(i, 0, m) if (pth[t] >> i & 1) if (laste == -1 || h[ef[lck[i]]] > h[ef[lck[laste]]]) laste = i;
bkdfs(laste);
int ans = INF;
FOR(v, 0, m)
{
int cs = h[ky[lck[v]]] + h[ky[lck[v]]] + h[ef[lck[v]]] - 2 * h[getlca(ky[lck[v]], ef[lck[v]])];
ans = min(ans, cs + dp[tot][v]);
}
if (ans >= INF) return cout << "-1\n", 0;
ans += h[t] - h[ef[lck[laste]]];
cout << ans << endl;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
14 ms |
24012 KB |
Output is correct |
2 |
Correct |
13 ms |
24016 KB |
Output is correct |
3 |
Correct |
75 ms |
39188 KB |
Output is correct |
4 |
Correct |
72 ms |
39136 KB |
Output is correct |
5 |
Correct |
83 ms |
39272 KB |
Output is correct |
6 |
Correct |
72 ms |
39148 KB |
Output is correct |
7 |
Correct |
76 ms |
39216 KB |
Output is correct |
8 |
Correct |
75 ms |
39364 KB |
Output is correct |
9 |
Correct |
71 ms |
39492 KB |
Output is correct |
10 |
Correct |
72 ms |
39216 KB |
Output is correct |
11 |
Correct |
79 ms |
39332 KB |
Output is correct |
12 |
Correct |
67 ms |
41224 KB |
Output is correct |
13 |
Correct |
68 ms |
42048 KB |
Output is correct |
14 |
Correct |
68 ms |
41684 KB |
Output is correct |
15 |
Correct |
69 ms |
42704 KB |
Output is correct |
16 |
Correct |
70 ms |
43500 KB |
Output is correct |
17 |
Correct |
71 ms |
43464 KB |
Output is correct |
18 |
Correct |
71 ms |
43912 KB |
Output is correct |
19 |
Correct |
75 ms |
48084 KB |
Output is correct |
20 |
Correct |
72 ms |
47800 KB |
Output is correct |
21 |
Correct |
72 ms |
47584 KB |
Output is correct |
22 |
Correct |
14 ms |
24012 KB |
Output is correct |
23 |
Correct |
13 ms |
24012 KB |
Output is correct |
24 |
Correct |
15 ms |
23980 KB |
Output is correct |
25 |
Correct |
13 ms |
24036 KB |
Output is correct |
26 |
Correct |
13 ms |
23804 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
14 ms |
23980 KB |
Output is correct |
2 |
Correct |
15 ms |
24052 KB |
Output is correct |
3 |
Correct |
14 ms |
24140 KB |
Output is correct |
4 |
Correct |
14 ms |
24140 KB |
Output is correct |
5 |
Correct |
170 ms |
70236 KB |
Output is correct |
6 |
Correct |
143 ms |
70284 KB |
Output is correct |
7 |
Correct |
195 ms |
70348 KB |
Output is correct |
8 |
Correct |
147 ms |
70332 KB |
Output is correct |
9 |
Correct |
167 ms |
70336 KB |
Output is correct |
10 |
Correct |
110 ms |
70348 KB |
Output is correct |
11 |
Correct |
110 ms |
70348 KB |
Output is correct |
12 |
Correct |
115 ms |
70468 KB |
Output is correct |
13 |
Correct |
109 ms |
70252 KB |
Output is correct |
14 |
Correct |
111 ms |
70360 KB |
Output is correct |
15 |
Correct |
152 ms |
70372 KB |
Output is correct |
16 |
Correct |
190 ms |
70432 KB |
Output is correct |
17 |
Correct |
155 ms |
70340 KB |
Output is correct |
18 |
Correct |
113 ms |
70408 KB |
Output is correct |
19 |
Correct |
112 ms |
70516 KB |
Output is correct |
20 |
Correct |
110 ms |
70476 KB |
Output is correct |
21 |
Correct |
110 ms |
70684 KB |
Output is correct |
22 |
Correct |
111 ms |
70788 KB |
Output is correct |
23 |
Correct |
110 ms |
70772 KB |
Output is correct |
24 |
Correct |
109 ms |
70800 KB |
Output is correct |
25 |
Correct |
832 ms |
114328 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
14 ms |
24012 KB |
Output is correct |
2 |
Correct |
13 ms |
24016 KB |
Output is correct |
3 |
Correct |
75 ms |
39188 KB |
Output is correct |
4 |
Correct |
72 ms |
39136 KB |
Output is correct |
5 |
Correct |
83 ms |
39272 KB |
Output is correct |
6 |
Correct |
72 ms |
39148 KB |
Output is correct |
7 |
Correct |
76 ms |
39216 KB |
Output is correct |
8 |
Correct |
75 ms |
39364 KB |
Output is correct |
9 |
Correct |
71 ms |
39492 KB |
Output is correct |
10 |
Correct |
72 ms |
39216 KB |
Output is correct |
11 |
Correct |
79 ms |
39332 KB |
Output is correct |
12 |
Correct |
67 ms |
41224 KB |
Output is correct |
13 |
Correct |
68 ms |
42048 KB |
Output is correct |
14 |
Correct |
68 ms |
41684 KB |
Output is correct |
15 |
Correct |
69 ms |
42704 KB |
Output is correct |
16 |
Correct |
70 ms |
43500 KB |
Output is correct |
17 |
Correct |
71 ms |
43464 KB |
Output is correct |
18 |
Correct |
71 ms |
43912 KB |
Output is correct |
19 |
Correct |
75 ms |
48084 KB |
Output is correct |
20 |
Correct |
72 ms |
47800 KB |
Output is correct |
21 |
Correct |
72 ms |
47584 KB |
Output is correct |
22 |
Correct |
14 ms |
24012 KB |
Output is correct |
23 |
Correct |
13 ms |
24012 KB |
Output is correct |
24 |
Correct |
15 ms |
23980 KB |
Output is correct |
25 |
Correct |
13 ms |
24036 KB |
Output is correct |
26 |
Correct |
13 ms |
23804 KB |
Output is correct |
27 |
Correct |
14 ms |
23980 KB |
Output is correct |
28 |
Correct |
15 ms |
24052 KB |
Output is correct |
29 |
Correct |
14 ms |
24140 KB |
Output is correct |
30 |
Correct |
14 ms |
24140 KB |
Output is correct |
31 |
Correct |
170 ms |
70236 KB |
Output is correct |
32 |
Correct |
143 ms |
70284 KB |
Output is correct |
33 |
Correct |
195 ms |
70348 KB |
Output is correct |
34 |
Correct |
147 ms |
70332 KB |
Output is correct |
35 |
Correct |
167 ms |
70336 KB |
Output is correct |
36 |
Correct |
110 ms |
70348 KB |
Output is correct |
37 |
Correct |
110 ms |
70348 KB |
Output is correct |
38 |
Correct |
115 ms |
70468 KB |
Output is correct |
39 |
Correct |
109 ms |
70252 KB |
Output is correct |
40 |
Correct |
111 ms |
70360 KB |
Output is correct |
41 |
Correct |
152 ms |
70372 KB |
Output is correct |
42 |
Correct |
190 ms |
70432 KB |
Output is correct |
43 |
Correct |
155 ms |
70340 KB |
Output is correct |
44 |
Correct |
113 ms |
70408 KB |
Output is correct |
45 |
Correct |
112 ms |
70516 KB |
Output is correct |
46 |
Correct |
110 ms |
70476 KB |
Output is correct |
47 |
Correct |
110 ms |
70684 KB |
Output is correct |
48 |
Correct |
111 ms |
70788 KB |
Output is correct |
49 |
Correct |
110 ms |
70772 KB |
Output is correct |
50 |
Correct |
109 ms |
70800 KB |
Output is correct |
51 |
Correct |
832 ms |
114328 KB |
Output is correct |
52 |
Correct |
1196 ms |
194972 KB |
Output is correct |
53 |
Correct |
1212 ms |
195012 KB |
Output is correct |
54 |
Correct |
1187 ms |
192796 KB |
Output is correct |
55 |
Correct |
1223 ms |
192112 KB |
Output is correct |
56 |
Correct |
1210 ms |
193144 KB |
Output is correct |
57 |
Correct |
1250 ms |
194820 KB |
Output is correct |
58 |
Correct |
13 ms |
24012 KB |
Output is correct |
59 |
Correct |
14 ms |
24012 KB |
Output is correct |
60 |
Correct |
14 ms |
24084 KB |
Output is correct |
61 |
Correct |
1221 ms |
195072 KB |
Output is correct |
62 |
Correct |
1252 ms |
203220 KB |
Output is correct |
63 |
Correct |
1225 ms |
197572 KB |
Output is correct |
64 |
Correct |
92 ms |
42436 KB |
Output is correct |
65 |
Correct |
86 ms |
42844 KB |
Output is correct |
66 |
Correct |
1204 ms |
195040 KB |
Output is correct |
67 |
Correct |
1226 ms |
194712 KB |
Output is correct |
68 |
Correct |
1105 ms |
235460 KB |
Output is correct |
69 |
Correct |
1062 ms |
235888 KB |
Output is correct |
70 |
Correct |
1100 ms |
235220 KB |
Output is correct |
71 |
Correct |
1169 ms |
235276 KB |
Output is correct |
72 |
Correct |
1106 ms |
235120 KB |
Output is correct |
73 |
Correct |
1020 ms |
236636 KB |
Output is correct |
74 |
Correct |
1085 ms |
237380 KB |
Output is correct |
75 |
Correct |
1090 ms |
237316 KB |
Output is correct |
76 |
Correct |
1078 ms |
238052 KB |
Output is correct |
77 |
Correct |
1083 ms |
236876 KB |
Output is correct |
78 |
Correct |
1105 ms |
244792 KB |
Output is correct |
79 |
Correct |
1049 ms |
244424 KB |
Output is correct |
80 |
Correct |
1004 ms |
242888 KB |
Output is correct |
81 |
Correct |
985 ms |
259476 KB |
Output is correct |
82 |
Correct |
1043 ms |
260836 KB |
Output is correct |
83 |
Correct |
1012 ms |
260804 KB |
Output is correct |
84 |
Correct |
1030 ms |
271924 KB |
Output is correct |
85 |
Correct |
1069 ms |
309800 KB |
Output is correct |
86 |
Correct |
1063 ms |
308772 KB |
Output is correct |
87 |
Correct |
1071 ms |
308884 KB |
Output is correct |