#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef long double ld;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
set<int> S;
struct Graph
{
struct edge
{
int v; ll weight; int id;
};
vector<vector<edge> > adj;
int n;
Graph(int _n)
{
adj.resize(_n);
n = _n;
}
void addedge(int u, int v, ll c, int id)
{
edge tmp;
tmp.v = v; tmp.weight = c; tmp.id=id;
adj[u].pb(tmp);
}
void reset()
{
adj.clear();
}
vector<ll> dist;
vi par;
void bfs(int s)
{
ll INFI = ll(1e18);
dist.assign(n, INFI);
par.assign(n, -1);
dist[s] = 0; par[s] = -1;
queue<int> q; q.push(s);
while(!q.empty())
{
int u = q.front(); q.pop();
for(int i = 0; i < adj[u].size(); i++)
{
int v = adj[u][i].v;
if(dist[v] >= INFI)
{
dist[v] = dist[u] + 1;
par[v] = u;
q.push(v);
}
}
}
}
void bfs01(int s)
{
ll INFI = ll(1e18);
dist.assign(n, INFI);
par.assign(n, -1);
dist[s] = 0; par[s] = -1;
deque<int> q; q.pb(s);
while(!q.empty())
{
int u = q.front(); q.pop_front();
for(int i = 0; i < adj[u].size(); i++)
{
int v = adj[u][i].v; ll w = adj[u][i].weight;
if(dist[v] >= INFI)
{
if(w == 1)
{
dist[v] = dist[u] + 1;
par[v] = u;
q.push_back(v);
}
else
{
dist[v] = dist[u];
par[v] = u;
q.push_front(v);
}
}
}
}
}
void dijkstra(int s, int mode=1)
{
ll INFI = ll(1e18);
dist.clear();
dist.assign(n, INFI);
par.assign(n, -1);
dist[s] = 0; par[s] = -1;
priority_queue<ii, vector<ii>, greater<ii> > pq;
pq.push(ii(0, s));
while(!pq.empty())
{
int u = pq.top().se; ll d = pq.top().fi; pq.pop();
for(int i = 0; i < adj[u].size(); i++)
{
int v = adj[u][i].v; ll w = adj[u][i].weight;
if(d + w < dist[v])
{
dist[v] = d + w;
par[v] = u;
//cerr<<"ADD "<<adj[u][i].id<<'\n';
if(mode) S.insert(adj[u][i].id);
pq.push(ii(dist[v], v));
}
}
}
}
vector<vector<ll> > d;
void Floyd()
{
ll INFIN = ll(1e18);
d.resize(n);
for(int i = 0; i < n; i++)
{
d[i].assign(n, INFIN);
}
for(int i = 0; i < n; i++)
{
for(int j = 0; j < adj[i].size(); j++)
{
d[i][adj[i][j].v] = min(d[i][adj[i][j].v],adj[i][j].weight);
}
d[i][i] = 0;
}
for(int k = 0; k < n; k++)
{
for(int i = 0; i < n; i++)
{
for(int j = 0; j < n; j++)
{
d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
}
}
}
}
};
ll D[55555];
vector<pair<ii,ii> > edges;
int n,m;
ll res=ll(1e18);
void test(int id)
{
Graph G(n);
for(int i=0;i<m;i++)
{
int u=edges[i].fi.fi; int v=edges[i].fi.se;
if(i==id) swap(u,v);
G.addedge(u,v,edges[i].se.fi,edges[i].se.se);
}
G.dijkstra(0,0);
ll ans = G.dist[n-1];
G.dijkstra(n-1,0);
ans+=G.dist[0];
ans+=D[id];
res=min(res,ans);
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
cin>>n>>m;
Graph ori(n),rev(n),oriunw(n),revunw(n);
vector<ii> VV;
int all0=1;
map<ii,ii> ma;
for(int i=0;i<m;i++)
{
int u,v,c,d;
cin>>u>>v>>c>>d;
if(c!=0) all0=0;
VV.pb({d,i});
u--; v--;
if(ma.find({u,v})==ma.end())
{
ma[{u,v}]={c+d,i};
}
else
{
ma[{u,v}]=min(ma[{u,v}],{c+d,i});
}
D[i]=d;
edges.pb({{u,v},{c,d}});
ori.addedge(u,v,c,i);
oriunw.addedge(u,v,1,i);
rev.addedge(v,u,c,i);
revunw.addedge(v,u,1,i);
}
int sub2=1;
if(m%2==0)
{
for(int i=0;i<m;i+=2)
{
int a1 = edges[i].se.se;
int a2 = edges[i+1].se.se;
edges[i].se.se=edges[i+1].se.se=0;
if(edges[i]!=edges[i+1]) sub2=0;
edges[i].se.se=a1; edges[i+1].se.se=a2;
}
}
else sub2=0;
ori.Floyd();
ori.dijkstra(0);
sort(VV.begin(),VV.end());
//for(int i=0;i<min(100,m);i++) S.insert(VV[i].se);
ll as = ori.dist[n-1];
ori.dijkstra(n-1);
as+=ori.dist[0];
rev.dijkstra(n-1);
res=min(res,as);
//assert(sub2);
if(sub2)
{
for(auto E:edges)
{
int u=E.fi.fi; int v=E.fi.se;
ll c=E.se.fi; ll d=E.se.se;
//should i add the edge v->u
res=min(res,d+ori.d[0][n-1]+ori.d[n-1][v]+c+ori.d[u][0]);
res=min(res,d+ori.d[0][v]+c+ori.d[u][n-1]+ori.d[n-1][0]);
res=min(res,d+ori.d[0][v]+c+ori.d[u][n-1]+ori.d[n-1][v]+c+ori.d[u][0]);
res=min(res,ori.d[0][n-1]+ori.d[n-1][0]);
}
}
else
{
vi nw;
for(int s:S)
{
int u=edges[s].fi.fi; int v=edges[s].fi.se;
nw.pb(ma[{u,v}].se);
}
for(int s:nw)
{
test(s);
}
}
if(res>=ll(1e18)) res=-1;
cout<<res<<'\n';
}
Compilation message
ho_t4.cpp: In member function 'void Graph::bfs(int)':
ho_t4.cpp:62:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i < adj[u].size(); i++)
~~^~~~~~~~~~~~~~~
ho_t4.cpp: In member function 'void Graph::bfs01(int)':
ho_t4.cpp:85:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i < adj[u].size(); i++)
~~^~~~~~~~~~~~~~~
ho_t4.cpp: In member function 'void Graph::dijkstra(int, int)':
ho_t4.cpp:119:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i < adj[u].size(); i++)
~~^~~~~~~~~~~~~~~
ho_t4.cpp: In member function 'void Graph::Floyd()':
ho_t4.cpp:146:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0; j < adj[i].size(); j++)
~~^~~~~~~~~~~~~~~
ho_t4.cpp: In function 'int main()':
ho_t4.cpp:193:6: warning: variable 'all0' set but not used [-Wunused-but-set-variable]
int all0=1;
^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
51 ms |
1016 KB |
Output is correct |
| 2 |
Correct |
16 ms |
760 KB |
Output is correct |
| 3 |
Correct |
79 ms |
1016 KB |
Output is correct |
| 4 |
Correct |
89 ms |
1016 KB |
Output is correct |
| 5 |
Correct |
19 ms |
632 KB |
Output is correct |
| 6 |
Correct |
15 ms |
760 KB |
Output is correct |
| 7 |
Correct |
5 ms |
376 KB |
Output is correct |
| 8 |
Correct |
5 ms |
376 KB |
Output is correct |
| 9 |
Correct |
5 ms |
504 KB |
Output is correct |
| 10 |
Correct |
125 ms |
1016 KB |
Output is correct |
| 11 |
Correct |
131 ms |
1016 KB |
Output is correct |
| 12 |
Correct |
130 ms |
1016 KB |
Output is correct |
| 13 |
Incorrect |
38 ms |
1016 KB |
Output isn't correct |
| 14 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
74 ms |
10676 KB |
Output is correct |
| 2 |
Correct |
73 ms |
10080 KB |
Output is correct |
| 3 |
Correct |
82 ms |
10080 KB |
Output is correct |
| 4 |
Correct |
16 ms |
1144 KB |
Output is correct |
| 5 |
Correct |
14 ms |
888 KB |
Output is correct |
| 6 |
Correct |
16 ms |
760 KB |
Output is correct |
| 7 |
Correct |
14 ms |
888 KB |
Output is correct |
| 8 |
Correct |
5 ms |
376 KB |
Output is correct |
| 9 |
Correct |
73 ms |
10600 KB |
Output is correct |
| 10 |
Correct |
77 ms |
10596 KB |
Output is correct |
| 11 |
Correct |
75 ms |
9956 KB |
Output is correct |
| 12 |
Correct |
83 ms |
9828 KB |
Output is correct |
| 13 |
Correct |
71 ms |
10084 KB |
Output is correct |
| 14 |
Correct |
72 ms |
10852 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
50 ms |
1016 KB |
Output is correct |
| 2 |
Correct |
17 ms |
760 KB |
Output is correct |
| 3 |
Correct |
872 ms |
10248 KB |
Output is correct |
| 4 |
Correct |
16 ms |
760 KB |
Output is correct |
| 5 |
Execution timed out |
1093 ms |
12408 KB |
Time limit exceeded |
| 6 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
51 ms |
1016 KB |
Output is correct |
| 2 |
Correct |
16 ms |
760 KB |
Output is correct |
| 3 |
Correct |
79 ms |
1016 KB |
Output is correct |
| 4 |
Correct |
89 ms |
1016 KB |
Output is correct |
| 5 |
Correct |
19 ms |
632 KB |
Output is correct |
| 6 |
Correct |
15 ms |
760 KB |
Output is correct |
| 7 |
Correct |
5 ms |
376 KB |
Output is correct |
| 8 |
Correct |
5 ms |
376 KB |
Output is correct |
| 9 |
Correct |
5 ms |
504 KB |
Output is correct |
| 10 |
Correct |
125 ms |
1016 KB |
Output is correct |
| 11 |
Correct |
131 ms |
1016 KB |
Output is correct |
| 12 |
Correct |
130 ms |
1016 KB |
Output is correct |
| 13 |
Incorrect |
38 ms |
1016 KB |
Output isn't correct |
| 14 |
Halted |
0 ms |
0 KB |
- |
