#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define sp ' '
#define en '\n'
#define smin(a, b) a = min(a, b)
#define smax(a, b) a = max(a, b)
using namespace std;
const int N = 1e5 + 2;
const int mod = 1e9 + 7;
const ll linf = 1e18;
int par[N][17];
ll mn[N][17];
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int n, s, q, e;
cin >> n >> s >> q >> e;
e -= 1;
vector<int> u(n), v(n), w(n);
vector<vector<array<int, 2>>> g(n);
for (int i = 0; i < n - 1; i++) {
cin >> u[i] >> v[i] >> w[i];
u[i] -= 1; v[i] -= 1;
g[u[i]].push_back({v[i], i});
g[v[i]].push_back({u[i], i});
}
vector<bool> is(n);
for (int i = 0; i < s; i++) {
int x; cin >> x; x -= 1;
is[x] = 1;
}
vector<int> in(n), out(n), dep(n);
int tsz = -1;
vector<ll> opt(n, linf), pref(n);
function<void(int, int, ll)> Dfs = [&] (int s, int e, ll o) {
in[s] = ++tsz;
pref[s] = o;
par[s][0] = e;
for (int i = 1; i < 17; i++) {
if (par[s][i - 1] != -1) par[s][i] = par[par[s][i - 1]][i - 1];
else par[s][i] = -1;
}
for (auto u : g[s]) {
if (u[0] == e) continue;
dep[u[0]] = dep[s] + 1;
Dfs(u[0], s, o + w[u[1]]);
smin(opt[s], opt[u[0]] + w[u[1]]);
}
if (is[s] == 1) opt[s] = 0;
out[s] = tsz;
};
Dfs(e, -1, 0);
for (int i = 0; i < n - 1; i++) {
if (in[u[i]] > in[v[i]]) swap(u[i], v[i]);
}
for (int i = 0; i < n; i++) {
if (opt[i] != linf) opt[i] -= pref[i];
}
function<void(int, int)> Dfs1 = [&] (int s, int e) {
mn[s][0] = opt[s];
for (int i = 1; i < 17; i++) {
mn[s][i] = mn[s][i - 1];
if (par[s][i - 1] != -1) smin(mn[s][i], mn[par[s][i - 1]][i - 1]);
}
for (auto u : g[s]) {
if (u[0] == e) continue;
Dfs1(u[0], s);
}
};
Dfs1(e, -1);
auto Get = [&] (int l, int r) {
int kol = dep[r] - dep[l];
ll ans = linf;
for (int i = 16; i >= 0; i--) {
if ((1 << i) & kol) {
smin(ans, mn[r][i]);
r = par[r][i];
}
}
return min(opt[l], ans);
};
while (q--) {
int x, y;
cin >> x >> y;
x -= 1; y -= 1;
if (!(in[v[x]] <= in[y] && out[y] <= out[v[x]])) {
cout << "escaped" << en;
continue;
}
if (opt[v[x]] == linf) {
cout << "oo" << en;
continue;
}
ll ans = pref[y] + Get(v[x], y);
cout << ans << en;
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
468 KB |
Output is correct |
2 |
Correct |
3 ms |
468 KB |
Output is correct |
3 |
Correct |
3 ms |
468 KB |
Output is correct |
4 |
Correct |
3 ms |
464 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
468 KB |
Output is correct |
2 |
Correct |
3 ms |
468 KB |
Output is correct |
3 |
Correct |
3 ms |
468 KB |
Output is correct |
4 |
Correct |
3 ms |
464 KB |
Output is correct |
5 |
Correct |
1 ms |
596 KB |
Output is correct |
6 |
Correct |
1 ms |
596 KB |
Output is correct |
7 |
Correct |
1 ms |
596 KB |
Output is correct |
8 |
Correct |
1 ms |
596 KB |
Output is correct |
9 |
Correct |
1 ms |
596 KB |
Output is correct |
10 |
Correct |
1 ms |
596 KB |
Output is correct |
11 |
Correct |
2 ms |
600 KB |
Output is correct |
12 |
Correct |
1 ms |
596 KB |
Output is correct |
13 |
Correct |
1 ms |
596 KB |
Output is correct |
14 |
Correct |
1 ms |
672 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
159 ms |
34992 KB |
Output is correct |
2 |
Correct |
145 ms |
34608 KB |
Output is correct |
3 |
Correct |
155 ms |
34504 KB |
Output is correct |
4 |
Correct |
212 ms |
37772 KB |
Output is correct |
5 |
Correct |
159 ms |
37780 KB |
Output is correct |
6 |
Correct |
181 ms |
41472 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
3 ms |
468 KB |
Output is correct |
2 |
Correct |
3 ms |
468 KB |
Output is correct |
3 |
Correct |
3 ms |
468 KB |
Output is correct |
4 |
Correct |
3 ms |
464 KB |
Output is correct |
5 |
Correct |
1 ms |
596 KB |
Output is correct |
6 |
Correct |
1 ms |
596 KB |
Output is correct |
7 |
Correct |
1 ms |
596 KB |
Output is correct |
8 |
Correct |
1 ms |
596 KB |
Output is correct |
9 |
Correct |
1 ms |
596 KB |
Output is correct |
10 |
Correct |
1 ms |
596 KB |
Output is correct |
11 |
Correct |
2 ms |
600 KB |
Output is correct |
12 |
Correct |
1 ms |
596 KB |
Output is correct |
13 |
Correct |
1 ms |
596 KB |
Output is correct |
14 |
Correct |
1 ms |
672 KB |
Output is correct |
15 |
Correct |
159 ms |
34992 KB |
Output is correct |
16 |
Correct |
145 ms |
34608 KB |
Output is correct |
17 |
Correct |
155 ms |
34504 KB |
Output is correct |
18 |
Correct |
212 ms |
37772 KB |
Output is correct |
19 |
Correct |
159 ms |
37780 KB |
Output is correct |
20 |
Correct |
181 ms |
41472 KB |
Output is correct |
21 |
Correct |
124 ms |
34356 KB |
Output is correct |
22 |
Correct |
133 ms |
34056 KB |
Output is correct |
23 |
Correct |
159 ms |
34036 KB |
Output is correct |
24 |
Correct |
154 ms |
37784 KB |
Output is correct |
25 |
Correct |
173 ms |
42604 KB |
Output is correct |
26 |
Correct |
147 ms |
34532 KB |
Output is correct |
27 |
Correct |
125 ms |
34004 KB |
Output is correct |
28 |
Correct |
135 ms |
34064 KB |
Output is correct |
29 |
Correct |
174 ms |
36424 KB |
Output is correct |
30 |
Correct |
185 ms |
38964 KB |
Output is correct |
31 |
Correct |
133 ms |
34472 KB |
Output is correct |
32 |
Correct |
140 ms |
34188 KB |
Output is correct |
33 |
Correct |
143 ms |
34240 KB |
Output is correct |
34 |
Correct |
175 ms |
37428 KB |
Output is correct |
35 |
Correct |
175 ms |
42360 KB |
Output is correct |
36 |
Correct |
169 ms |
37708 KB |
Output is correct |