#include <bits/stdc++.h>
using namespace std;
#define int long long
using ii = pair <int, int>;
int n, m, k;
void read()
{
cin >> n >> m >> k;
}
struct vet
{
bool spec[511] = {false};
int a[511][511];
ii dp[511][511];
void calc()
{
memset(a, 0x3f3f, sizeof(a));
for (int i = 1; i <= n; ++i) a[i][i] = 0;
for (int i = 1; i <= m; ++i)
{
int u, v, L;
cin >> u >> v >> L;
a[u][v] = min(a[u][v], L);
a[v][u] = min(a[v][u], L);
}
for (int i = 1; i <= k; ++i)
{
int u;
cin >> u;
spec[u] = 1;
}
for (int k = 1; k <= n; ++k)
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= n; ++j)
a[i][j] = min(a[i][j], a[i][k]+a[k][j]);
for (int i = 1; i <= n; ++i)
{
for (int j = 1; j <= n; ++j)
if (spec[i] == 0 or spec[j] == 0 or i == j)
{
dp[i][j] = ii(1e9, j);
}
else dp[i][j] = ii(a[i][j], j);
sort (dp[i]+1, dp[i]+n+1);
}
int ans = LLONG_MAX;
for (int i = 1; i <= n; ++i)
for (int j = 1; j <= n; ++j)
for (int t = 1; t <= min(5ll, n); ++t)
for (int c = 1; c <= min(5ll, n); ++c)
if (i != j and i != dp[i][t].second and i != dp[j][c].second
and j != dp[i][t].second and j != dp[j][c].second
and dp[i][t].second != dp[j][c].second)
{
ans = min(ans, dp[i][t].first + dp[j][c].first);
}
cout << ans;
exit(0);
}
}Vetcan;
bool minimize(int &a, int b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
struct fullSub
{
vector <ii> g[100011];
int spec[100011];
tuple <int, int, int> best_pair()
{
vector <int> d(n+1, INT_MAX);
vector <int> head(n+1, 0);
priority_queue <ii, vector <ii>, greater <ii>> pq;
for (int i = 1; i <= n; ++i)
{
if (spec[i])
{
spec[i] = i;
d[i] = 0;
pq.emplace(d[i], i);
}
}
while (!pq.empty())
{
auto [du, u] = pq.top();
pq.pop();
if (d[u] != du)
continue;
for (auto [v, w] : g[u])
{
if (d[v] > d[u] + w)
{
d[v] = d[u] + w;
head[v] = head[u];
pq.emplace(d[v], v);
}
}
}
int best = INT_MAX;
int best_u = -1, best_v = -1;
for (int u = 1; u <= n; ++u)
{
for (auto [v, w] : g[u])
{
if (d[u] != INT_MAX and d[v] != INT_MAX
and head[u] != head[v])
{
if (minimize(best, d[u] + d[v] + w))
{
best = d[u] + d[v] + w;
best_u = head[u];
best_v = head[v];
}
}
}
}
return {best, best_u, best_v};
}
ii nearest_spec(int s)
{
vector <int> d(n+1, INT_MAX);
priority_queue <ii, vector <ii>, greater <ii>> pq;
d[s] = 0;
pq.emplace(d[s], s);
while (!pq.empty())
{
auto [du, u] = pq.top();
pq.pop();
if (d[u] != du)
continue;
if (spec[u])
{
return {d[u], u};
}
for (auto [v, w] : g[u])
{
if (d[v] > d[u] + w)
{
d[v] = d[u] + w;
pq.emplace(d[v], v);
}
}
}
return ii (INT_MAX, 0); /// khong toi duoc
}
void readMore()
{
while (m--)
{
int u, v, w;
cin >> u >> v >> w;
g[u].push_back(ii (v, w));
g[v].push_back(ii (u, w));
}
while (k--)
{
int u;
cin >> u;
spec[u] = 1;
}
}
void calc()
{
readMore();
/// giả sử tìm được đường đi ngắn nhất giữa 2 đỉnh bất kỳ
/// là từ u -> v
/// thì trong 4 số x1, y1, x2, y2 kiểu gì cũng có 1 số là u, 1 số là v
/// tại nếu không có thì thay thành (u, v) dĩ nhiên tốt hơn
/// để tìm từ u -> v thì push hết vào pq rồi dijsktra
auto [min_d, x, y] = best_pair();
int best = INT_MAX;
spec[x] = spec[y] = 0;
/// nếu (x1, x2) = (u, v) thì dijsktra giống như lúc tìm (u, v) để tính đán án
/// nếu x1 = u và y1 = v thì dijstra từ u và v để tìm đỉnh đặc biệt gần nó nhất
/// a = x, b = y
{
auto [sec_min_d, z, t] = best_pair();
minimize(best, min_d + sec_min_d);
}
/// a = x, c = y
{
auto [nearest_a, z] = nearest_spec(x);
spec[z] = 0;
auto [nearest_b, t] = nearest_spec(y);
minimize(best, nearest_a + nearest_b);
spec[z] = 1;
}
{
auto [nearest_a, z] = nearest_spec(y);
spec[z] = 0;
auto [nearest_b, t] = nearest_spec(x);
minimize(best, nearest_a + nearest_b);
spec[z] = 1;
}
cout << best;
}
}full;
signed main()
{
cin.tie(0)->sync_with_stdio(0);
#define task "cities"
if (fopen(task ".inp", "r"))
{
freopen(task ".inp", "r", stdin);
freopen(task ".out", "w", stdout);
}
read ();
full.calc();
return 0;
}
Compilation message
RelayMarathon.cpp: In function 'int main()':
RelayMarathon.cpp:250:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
250 | freopen(task ".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
RelayMarathon.cpp:251:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
251 | freopen(task ".out", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
19292 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
19292 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
50 ms |
28284 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
19292 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
