/*
+----------------------------------------------------------------+
| In the name of Allah, the most Gracious and the most Merciful. |
+----------------------------------------------------------------+
+------------------------------------------------------+
| Ба номи Худованди беандоза Mеҳрабон ва ниҳоят Бораҳм |
+------------------------------------------------------+
+-----------------------------------------+
| Во имя Аллаха Милостивого, Милосердного |
+-----------------------------------------+
This world is a trial for us
And we know well that we must
Obey the orders from my lord
To avoid all sins and seek reward
*/
# include <bits/stdc++.h>
# define FILE
using namespace std;
const int N = 3e5 + 100;
const long long inf = 1e15;
int n, m, timm, curr, bridge, U[N], V[N], W[N], maxW[N], tin[N], low[N];
long long dist[2][N], within[N], without[N];
vector < int > graph[N];
void bfs( int v, long long *dist ){
for( int i = 1; i <= n; i ++ ) dist[i] = inf;
dist[v] = 0;
priority_queue < pair <long long, int>, vector<pair<long long, int>>, greater<pair<long long, int> > > pq;
pq.push({0,v});
while( !pq.empty() ){
long long dst; int v; tie(dst, v) = pq.top(); pq.pop();
if( dst > dist[v] )continue;
for( auto i: graph[v] ){
int to = (v == V[i]?U[i]:V[i]);
if( dist[to] > dist[v] + W[i] ){
dist[to] = dist[v] + W[i];
pq.push({dist[to], to});
}
}
}
}
void dfs( int v, int f, int ras ){
tin[v] = low[v] = ++timm;
for( auto i: graph[v] ){
if( without[i] > ras )continue;
int to = (v==V[i]?U[i]:V[i]);
if( tin[to] <= curr ){
dfs(to, v, ras);
if( low[to] > tin[v] && tin[n] >= tin[to] && within[i] > ras )
bridge = 1;
else low[v] = min( low[v], low[to]);
}else if( to != f ){
low[v] = min( low[v], tin[to]);
}
}
}
bool check( long long ras){
curr = timm;
bridge = 0;
dfs(1, 0, ras);
//cout << "check " << curr << ' ' << tin[n] << ' ' <<bridge << endl;
if( tin[n] <= curr) return 0;
if( bridge )return 0;
return true;
}
int main(){
# ifdef FILEs
freopen( "input.txt", "r", stdin );
freopen( "output.txt", "w", stdout );
# endif
ios_base::sync_with_stdio(false);
cin >> n >> m;
for( int i = 1; i <= m; i ++ ){
cin >> V[i] >> U[i] >> W[i];
graph[V[i]].push_back( i );
graph[U[i]].push_back( i );
}
for( int i = m-1; i >= 1; i -- ){
maxW[i] = max( W[i+1], maxW[i+1]);
}
bfs( 1, dist[0]);
bfs( n, dist[1]);
for( int i = 1; i <= m; i ++ ){
without[i] = min( dist[0][V[i]] + dist[1][U[i]], dist[0][U[i]] + dist[1][V[i]]) + W[i];
within[i] = without[i] + maxW[i];
}
/*
for( int i = 1; i <= m; i ++ ){
cout << i << ' ' << V[i] <<' ' << U[i] << ' ' << without[i] << ' ' << within[i] <<' ' <<maxW[i]<< endl;
}cout << endl;
*/
long long l = dist[0][n]-1, r = dist[0][n] + maxW[1];
while( r - l > 1 ){
long long mid = ( l + r ) >> 1;
//cout << l << ' '<< mid << ' ' << r << endl;
if( check(mid) )
r = mid;
else
l = mid;
}
cout << r;
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
7424 KB |
Output is correct |
2 |
Correct |
5 ms |
7424 KB |
Output is correct |
3 |
Incorrect |
5 ms |
7424 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
7424 KB |
Output is correct |
2 |
Correct |
5 ms |
7424 KB |
Output is correct |
3 |
Incorrect |
5 ms |
7424 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
546 ms |
31584 KB |
Output is correct |
2 |
Correct |
548 ms |
31908 KB |
Output is correct |
3 |
Correct |
535 ms |
31352 KB |
Output is correct |
4 |
Correct |
530 ms |
31352 KB |
Output is correct |
5 |
Correct |
533 ms |
31352 KB |
Output is correct |
6 |
Correct |
543 ms |
32032 KB |
Output is correct |
7 |
Correct |
550 ms |
31864 KB |
Output is correct |
8 |
Correct |
580 ms |
32120 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
557 ms |
31992 KB |
Output is correct |
2 |
Correct |
555 ms |
31568 KB |
Output is correct |
3 |
Correct |
553 ms |
31608 KB |
Output is correct |
4 |
Correct |
573 ms |
31992 KB |
Output is correct |
5 |
Correct |
549 ms |
31480 KB |
Output is correct |
6 |
Correct |
545 ms |
31608 KB |
Output is correct |
7 |
Correct |
563 ms |
31672 KB |
Output is correct |
8 |
Correct |
551 ms |
31864 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
484 ms |
28596 KB |
Output is correct |
2 |
Correct |
198 ms |
32760 KB |
Output is correct |
3 |
Correct |
266 ms |
32120 KB |
Output is correct |
4 |
Correct |
286 ms |
32120 KB |
Output is correct |
5 |
Correct |
274 ms |
32376 KB |
Output is correct |
6 |
Correct |
265 ms |
32376 KB |
Output is correct |
7 |
Correct |
276 ms |
32376 KB |
Output is correct |
8 |
Correct |
273 ms |
32504 KB |
Output is correct |
9 |
Correct |
264 ms |
32120 KB |
Output is correct |
10 |
Correct |
287 ms |
32504 KB |
Output is correct |
11 |
Correct |
267 ms |
32284 KB |
Output is correct |
12 |
Correct |
459 ms |
28700 KB |
Output is correct |
13 |
Correct |
263 ms |
32248 KB |
Output is correct |
14 |
Correct |
144 ms |
36716 KB |
Output is correct |
15 |
Correct |
146 ms |
36856 KB |
Output is correct |
16 |
Correct |
448 ms |
28504 KB |
Output is correct |
17 |
Correct |
452 ms |
28088 KB |
Output is correct |
18 |
Correct |
445 ms |
28516 KB |
Output is correct |
19 |
Correct |
201 ms |
32760 KB |
Output is correct |
20 |
Correct |
202 ms |
32760 KB |
Output is correct |
21 |
Correct |
203 ms |
32760 KB |
Output is correct |
22 |
Correct |
201 ms |
32760 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
484 ms |
28596 KB |
Output is correct |
2 |
Correct |
198 ms |
32760 KB |
Output is correct |
3 |
Correct |
266 ms |
32120 KB |
Output is correct |
4 |
Correct |
286 ms |
32120 KB |
Output is correct |
5 |
Correct |
274 ms |
32376 KB |
Output is correct |
6 |
Correct |
265 ms |
32376 KB |
Output is correct |
7 |
Correct |
276 ms |
32376 KB |
Output is correct |
8 |
Correct |
273 ms |
32504 KB |
Output is correct |
9 |
Correct |
264 ms |
32120 KB |
Output is correct |
10 |
Correct |
287 ms |
32504 KB |
Output is correct |
11 |
Correct |
267 ms |
32284 KB |
Output is correct |
12 |
Correct |
459 ms |
28700 KB |
Output is correct |
13 |
Correct |
263 ms |
32248 KB |
Output is correct |
14 |
Correct |
144 ms |
36716 KB |
Output is correct |
15 |
Correct |
146 ms |
36856 KB |
Output is correct |
16 |
Correct |
448 ms |
28504 KB |
Output is correct |
17 |
Correct |
452 ms |
28088 KB |
Output is correct |
18 |
Correct |
445 ms |
28516 KB |
Output is correct |
19 |
Correct |
201 ms |
32760 KB |
Output is correct |
20 |
Correct |
202 ms |
32760 KB |
Output is correct |
21 |
Correct |
203 ms |
32760 KB |
Output is correct |
22 |
Correct |
201 ms |
32760 KB |
Output is correct |
23 |
Correct |
502 ms |
29616 KB |
Output is correct |
24 |
Correct |
259 ms |
32760 KB |
Output is correct |
25 |
Correct |
255 ms |
27384 KB |
Output is correct |
26 |
Correct |
266 ms |
26744 KB |
Output is correct |
27 |
Correct |
259 ms |
26744 KB |
Output is correct |
28 |
Correct |
261 ms |
27512 KB |
Output is correct |
29 |
Correct |
244 ms |
26744 KB |
Output is correct |
30 |
Correct |
251 ms |
27128 KB |
Output is correct |
31 |
Correct |
255 ms |
27128 KB |
Output is correct |
32 |
Correct |
249 ms |
26872 KB |
Output is correct |
33 |
Correct |
263 ms |
27272 KB |
Output is correct |
34 |
Correct |
503 ms |
28672 KB |
Output is correct |
35 |
Correct |
267 ms |
27000 KB |
Output is correct |
36 |
Correct |
166 ms |
38644 KB |
Output is correct |
37 |
Correct |
172 ms |
38584 KB |
Output is correct |
38 |
Correct |
507 ms |
29304 KB |
Output is correct |
39 |
Correct |
493 ms |
28896 KB |
Output is correct |
40 |
Correct |
512 ms |
29752 KB |
Output is correct |
41 |
Correct |
249 ms |
33016 KB |
Output is correct |
42 |
Correct |
248 ms |
32888 KB |
Output is correct |
43 |
Correct |
249 ms |
32916 KB |
Output is correct |
44 |
Correct |
252 ms |
32888 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
5 ms |
7424 KB |
Output is correct |
2 |
Correct |
5 ms |
7424 KB |
Output is correct |
3 |
Incorrect |
5 ms |
7424 KB |
Output isn't correct |
4 |
Halted |
0 ms |
0 KB |
- |