#include <bits/stdc++.h>
typedef long long ll;
struct To {
ll v, w;
ll i;
};
struct Edge {
ll u, v, w;
};
const ll inf = 1e15;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
ll n, m;
std::cin >> n >> m;
std::vector<std::vector<To>> adj(n + 1);
std::vector<Edge> edges;
ll max_w = 0;
for (ll i = 0, u, v, w; i < m; ++i) {
std::cin >> u >> v >> w;
max_w = std::max(max_w, w);
adj[u].push_back({v, w, i});
adj[v].push_back({u, w, i});
edges.push_back({u, v, w});
}
auto sssp = [&](ll node) {
std::vector<ll> ans(n + 1, inf);
std::vector<bool> vis(n + 1);
std::priority_queue<std::pair<ll, ll>> pq;
ans[node] = 0;
pq.push({0, node});
while (!pq.empty()) {
auto [d, node] = pq.top();
d *= -1;
pq.pop();
if (vis[node]) {
continue;
}
vis[node] = true;
for (auto [ch, w, cur_i] : adj[node]) {
if (ans[ch] > d + w) {
ans[ch] = d + w;
pq.push({-ans[ch], ch});
}
}
}
return ans;
};
auto sssp1 = sssp(1);
auto ssspn = sssp(n);
std::vector<bool> active_edge(m), is_bridge(m), vis(n + 1), enc(n + 1);
std::vector<ll> low(n + 1), tin(n + 1);
auto check = [&](ll x) {
for (ll i = 0; i < m; ++i) {
auto [u, v, w] = edges[i];
active_edge[i] =
sssp1[u] + w + ssspn[v] <= x or sssp1[v] + w + ssspn[u] <= x;
}
vis.assign(n + 1, false);
enc.assign(n + 1, false);
enc[n] = true;
ll timer = 0;
std::function<void(ll, ll)> dfs;
dfs = [&](ll node, ll par) {
if (vis[node]) {
return;
}
vis[node] = true;
tin[node] = timer++;
low[node] = tin[node];
for (auto &[ch, w, i] : adj[node]) {
if (ch == par or !active_edge[i]) {
continue;
}
if (!vis[ch]) {
dfs(ch, node);
enc[node] = enc[node] || enc[ch];
}
is_bridge[i] = low[ch] > tin[node] and enc[ch];
low[node] = std::min(low[node], low[ch]);
}
};
dfs(1, 0);
ll worst_road = edges[m - 1].w;
for (ll i = m - 2; i >= 0; --i) {
auto [u, v, w] = edges[i];
if (is_bridge[i] and
std::min(sssp1[u] + ssspn[v], sssp1[v] + ssspn[u]) + w + worst_road >
x) {
return true;
}
worst_road = std::max(worst_road, edges[i].w);
}
return false;
};
ll s = sssp1[n], e = sssp1[n] + max_w;
while (s < e) {
ll m = s + (e - s) / 2;
if (check(m)) {
s = m + 1;
} else {
e = m;
}
}
std::cout << s << '\n';
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
1 ms |
604 KB |
Output is correct |
10 |
Correct |
2 ms |
604 KB |
Output is correct |
11 |
Correct |
2 ms |
668 KB |
Output is correct |
12 |
Correct |
2 ms |
604 KB |
Output is correct |
13 |
Correct |
1 ms |
604 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
600 KB |
Output is correct |
16 |
Correct |
2 ms |
604 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
280 ms |
43936 KB |
Output is correct |
2 |
Correct |
283 ms |
44268 KB |
Output is correct |
3 |
Correct |
289 ms |
43748 KB |
Output is correct |
4 |
Correct |
320 ms |
43660 KB |
Output is correct |
5 |
Correct |
290 ms |
44056 KB |
Output is correct |
6 |
Correct |
318 ms |
44872 KB |
Output is correct |
7 |
Correct |
359 ms |
44520 KB |
Output is correct |
8 |
Correct |
307 ms |
45028 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
291 ms |
45028 KB |
Output is correct |
2 |
Correct |
318 ms |
44356 KB |
Output is correct |
3 |
Correct |
290 ms |
44168 KB |
Output is correct |
4 |
Correct |
302 ms |
44736 KB |
Output is correct |
5 |
Correct |
291 ms |
43932 KB |
Output is correct |
6 |
Correct |
303 ms |
44080 KB |
Output is correct |
7 |
Correct |
325 ms |
44008 KB |
Output is correct |
8 |
Correct |
290 ms |
44516 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
236 ms |
40344 KB |
Output is correct |
2 |
Correct |
190 ms |
44996 KB |
Output is correct |
3 |
Correct |
151 ms |
50660 KB |
Output is correct |
4 |
Correct |
190 ms |
50668 KB |
Output is correct |
5 |
Correct |
153 ms |
50660 KB |
Output is correct |
6 |
Correct |
212 ms |
50916 KB |
Output is correct |
7 |
Correct |
187 ms |
50916 KB |
Output is correct |
8 |
Correct |
200 ms |
51172 KB |
Output is correct |
9 |
Correct |
197 ms |
50920 KB |
Output is correct |
10 |
Correct |
164 ms |
51432 KB |
Output is correct |
11 |
Correct |
166 ms |
51328 KB |
Output is correct |
12 |
Correct |
220 ms |
45028 KB |
Output is correct |
13 |
Correct |
177 ms |
51124 KB |
Output is correct |
14 |
Correct |
99 ms |
58856 KB |
Output is correct |
15 |
Correct |
91 ms |
58920 KB |
Output is correct |
16 |
Correct |
245 ms |
44968 KB |
Output is correct |
17 |
Correct |
218 ms |
43748 KB |
Output is correct |
18 |
Correct |
233 ms |
44516 KB |
Output is correct |
19 |
Correct |
151 ms |
45028 KB |
Output is correct |
20 |
Correct |
150 ms |
45088 KB |
Output is correct |
21 |
Correct |
160 ms |
45140 KB |
Output is correct |
22 |
Correct |
145 ms |
45004 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
236 ms |
40344 KB |
Output is correct |
2 |
Correct |
190 ms |
44996 KB |
Output is correct |
3 |
Correct |
151 ms |
50660 KB |
Output is correct |
4 |
Correct |
190 ms |
50668 KB |
Output is correct |
5 |
Correct |
153 ms |
50660 KB |
Output is correct |
6 |
Correct |
212 ms |
50916 KB |
Output is correct |
7 |
Correct |
187 ms |
50916 KB |
Output is correct |
8 |
Correct |
200 ms |
51172 KB |
Output is correct |
9 |
Correct |
197 ms |
50920 KB |
Output is correct |
10 |
Correct |
164 ms |
51432 KB |
Output is correct |
11 |
Correct |
166 ms |
51328 KB |
Output is correct |
12 |
Correct |
220 ms |
45028 KB |
Output is correct |
13 |
Correct |
177 ms |
51124 KB |
Output is correct |
14 |
Correct |
99 ms |
58856 KB |
Output is correct |
15 |
Correct |
91 ms |
58920 KB |
Output is correct |
16 |
Correct |
245 ms |
44968 KB |
Output is correct |
17 |
Correct |
218 ms |
43748 KB |
Output is correct |
18 |
Correct |
233 ms |
44516 KB |
Output is correct |
19 |
Correct |
151 ms |
45028 KB |
Output is correct |
20 |
Correct |
150 ms |
45088 KB |
Output is correct |
21 |
Correct |
160 ms |
45140 KB |
Output is correct |
22 |
Correct |
145 ms |
45004 KB |
Output is correct |
23 |
Correct |
276 ms |
45056 KB |
Output is correct |
24 |
Correct |
177 ms |
45288 KB |
Output is correct |
25 |
Correct |
167 ms |
44004 KB |
Output is correct |
26 |
Correct |
181 ms |
42460 KB |
Output is correct |
27 |
Correct |
163 ms |
42472 KB |
Output is correct |
28 |
Correct |
172 ms |
44264 KB |
Output is correct |
29 |
Correct |
182 ms |
42728 KB |
Output is correct |
30 |
Correct |
181 ms |
43260 KB |
Output is correct |
31 |
Correct |
178 ms |
43492 KB |
Output is correct |
32 |
Correct |
167 ms |
42724 KB |
Output is correct |
33 |
Correct |
176 ms |
44004 KB |
Output is correct |
34 |
Correct |
269 ms |
44776 KB |
Output is correct |
35 |
Correct |
166 ms |
43496 KB |
Output is correct |
36 |
Correct |
120 ms |
63204 KB |
Output is correct |
37 |
Correct |
123 ms |
65236 KB |
Output is correct |
38 |
Correct |
273 ms |
44516 KB |
Output is correct |
39 |
Correct |
276 ms |
44184 KB |
Output is correct |
40 |
Correct |
258 ms |
45032 KB |
Output is correct |
41 |
Correct |
192 ms |
45424 KB |
Output is correct |
42 |
Correct |
186 ms |
45032 KB |
Output is correct |
43 |
Correct |
199 ms |
45544 KB |
Output is correct |
44 |
Correct |
184 ms |
45212 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
1 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
348 KB |
Output is correct |
4 |
Correct |
0 ms |
348 KB |
Output is correct |
5 |
Correct |
0 ms |
348 KB |
Output is correct |
6 |
Correct |
0 ms |
348 KB |
Output is correct |
7 |
Correct |
0 ms |
348 KB |
Output is correct |
8 |
Correct |
0 ms |
348 KB |
Output is correct |
9 |
Correct |
1 ms |
604 KB |
Output is correct |
10 |
Correct |
2 ms |
604 KB |
Output is correct |
11 |
Correct |
2 ms |
668 KB |
Output is correct |
12 |
Correct |
2 ms |
604 KB |
Output is correct |
13 |
Correct |
1 ms |
604 KB |
Output is correct |
14 |
Correct |
1 ms |
604 KB |
Output is correct |
15 |
Correct |
1 ms |
600 KB |
Output is correct |
16 |
Correct |
2 ms |
604 KB |
Output is correct |
17 |
Correct |
280 ms |
43936 KB |
Output is correct |
18 |
Correct |
283 ms |
44268 KB |
Output is correct |
19 |
Correct |
289 ms |
43748 KB |
Output is correct |
20 |
Correct |
320 ms |
43660 KB |
Output is correct |
21 |
Correct |
290 ms |
44056 KB |
Output is correct |
22 |
Correct |
318 ms |
44872 KB |
Output is correct |
23 |
Correct |
359 ms |
44520 KB |
Output is correct |
24 |
Correct |
307 ms |
45028 KB |
Output is correct |
25 |
Correct |
291 ms |
45028 KB |
Output is correct |
26 |
Correct |
318 ms |
44356 KB |
Output is correct |
27 |
Correct |
290 ms |
44168 KB |
Output is correct |
28 |
Correct |
302 ms |
44736 KB |
Output is correct |
29 |
Correct |
291 ms |
43932 KB |
Output is correct |
30 |
Correct |
303 ms |
44080 KB |
Output is correct |
31 |
Correct |
325 ms |
44008 KB |
Output is correct |
32 |
Correct |
290 ms |
44516 KB |
Output is correct |
33 |
Correct |
236 ms |
40344 KB |
Output is correct |
34 |
Correct |
190 ms |
44996 KB |
Output is correct |
35 |
Correct |
151 ms |
50660 KB |
Output is correct |
36 |
Correct |
190 ms |
50668 KB |
Output is correct |
37 |
Correct |
153 ms |
50660 KB |
Output is correct |
38 |
Correct |
212 ms |
50916 KB |
Output is correct |
39 |
Correct |
187 ms |
50916 KB |
Output is correct |
40 |
Correct |
200 ms |
51172 KB |
Output is correct |
41 |
Correct |
197 ms |
50920 KB |
Output is correct |
42 |
Correct |
164 ms |
51432 KB |
Output is correct |
43 |
Correct |
166 ms |
51328 KB |
Output is correct |
44 |
Correct |
220 ms |
45028 KB |
Output is correct |
45 |
Correct |
177 ms |
51124 KB |
Output is correct |
46 |
Correct |
99 ms |
58856 KB |
Output is correct |
47 |
Correct |
91 ms |
58920 KB |
Output is correct |
48 |
Correct |
245 ms |
44968 KB |
Output is correct |
49 |
Correct |
218 ms |
43748 KB |
Output is correct |
50 |
Correct |
233 ms |
44516 KB |
Output is correct |
51 |
Correct |
151 ms |
45028 KB |
Output is correct |
52 |
Correct |
150 ms |
45088 KB |
Output is correct |
53 |
Correct |
160 ms |
45140 KB |
Output is correct |
54 |
Correct |
145 ms |
45004 KB |
Output is correct |
55 |
Correct |
276 ms |
45056 KB |
Output is correct |
56 |
Correct |
177 ms |
45288 KB |
Output is correct |
57 |
Correct |
167 ms |
44004 KB |
Output is correct |
58 |
Correct |
181 ms |
42460 KB |
Output is correct |
59 |
Correct |
163 ms |
42472 KB |
Output is correct |
60 |
Correct |
172 ms |
44264 KB |
Output is correct |
61 |
Correct |
182 ms |
42728 KB |
Output is correct |
62 |
Correct |
181 ms |
43260 KB |
Output is correct |
63 |
Correct |
178 ms |
43492 KB |
Output is correct |
64 |
Correct |
167 ms |
42724 KB |
Output is correct |
65 |
Correct |
176 ms |
44004 KB |
Output is correct |
66 |
Correct |
269 ms |
44776 KB |
Output is correct |
67 |
Correct |
166 ms |
43496 KB |
Output is correct |
68 |
Correct |
120 ms |
63204 KB |
Output is correct |
69 |
Correct |
123 ms |
65236 KB |
Output is correct |
70 |
Correct |
273 ms |
44516 KB |
Output is correct |
71 |
Correct |
276 ms |
44184 KB |
Output is correct |
72 |
Correct |
258 ms |
45032 KB |
Output is correct |
73 |
Correct |
192 ms |
45424 KB |
Output is correct |
74 |
Correct |
186 ms |
45032 KB |
Output is correct |
75 |
Correct |
199 ms |
45544 KB |
Output is correct |
76 |
Correct |
184 ms |
45212 KB |
Output is correct |
77 |
Correct |
314 ms |
47848 KB |
Output is correct |
78 |
Correct |
316 ms |
47400 KB |
Output is correct |
79 |
Correct |
289 ms |
53292 KB |
Output is correct |
80 |
Correct |
270 ms |
52968 KB |
Output is correct |
81 |
Correct |
279 ms |
52972 KB |
Output is correct |
82 |
Correct |
270 ms |
52744 KB |
Output is correct |
83 |
Correct |
264 ms |
53476 KB |
Output is correct |
84 |
Correct |
280 ms |
53736 KB |
Output is correct |
85 |
Correct |
264 ms |
52968 KB |
Output is correct |
86 |
Correct |
290 ms |
53160 KB |
Output is correct |
87 |
Correct |
271 ms |
53480 KB |
Output is correct |
88 |
Correct |
301 ms |
47172 KB |
Output is correct |
89 |
Correct |
275 ms |
53392 KB |
Output is correct |
90 |
Correct |
249 ms |
64032 KB |
Output is correct |
91 |
Correct |
275 ms |
65764 KB |
Output is correct |
92 |
Correct |
323 ms |
47660 KB |
Output is correct |
93 |
Correct |
303 ms |
46884 KB |
Output is correct |
94 |
Correct |
306 ms |
46316 KB |
Output is correct |
95 |
Correct |
326 ms |
47588 KB |
Output is correct |
96 |
Correct |
321 ms |
47592 KB |
Output is correct |
97 |
Correct |
336 ms |
47588 KB |
Output is correct |
98 |
Correct |
305 ms |
47552 KB |
Output is correct |