#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 2001;
typedef array<ll,3> T; // distance, begin, end
T ori = {INF,INF,INF};
template<class T> void MN (T& a, T b) { a = min(a,b); }
struct dat {
pi path;
vector<T> besPath;
dat() {}
dat(pi _path, vector<T> _besPath) {
path = _path;
T mn = ori; for (auto a: _besPath) MN(mn,a);
T bes[2][2]; F0R(i,2) F0R(j,2) bes[i][j] = ori;
bes[0][0] = mn;
for (auto a: _besPath) {
if (a[1] == mn[1]) {
if (a[2] != mn[2]) MN(bes[0][1],a);
} else {
MN(bes[1][0],a);
}
}
for (auto a: _besPath) if (a[1] != mn[1] && a[2] != bes[1][0][2]) bes[1][1] = a;
F0R(i,2) F0R(j,2) if (bes[i][j] != ori) besPath.pb(bes[i][j]);
}
};
dat comb(const dat& l, const dat& r) {
assert(l.path.s == r.path.f);
vector<T> cand;
for (auto a: l.besPath) for (auto b: r.besPath) if (a[2] != b[1])
cand.pb({a[0]+b[0],a[1],b[2]});
return dat({l.path.f,r.path.s},cand);
}
template<int SZ> struct Dijkstra {
pl dist[SZ][2];
vpi adj[SZ];
void addEdge(int A, int B, int C) {
adj[A].pb({B,C}), adj[B].pb({A,C});
}
void gen(T tmp) {
F0R(i,SZ) F0R(j,2) dist[i][j] = {INF,INF};
priority_queue<T,vector<T>,greater<T>> q;
dist[tmp[2]][0] = {tmp[0],tmp[1]};
q.push(tmp);
// cout << "ZZ " << tmp[2] << " " << dist[tmp[2]][0].f << "\n";
while (sz(q)) {
auto x = q.top(); q.pop();
bool ok = 0;
F0R(j,2) if (dist[x[2]][j] == mp(x[0],x[1])) ok = 1;
if (!ok) continue;
for (pi y: adj[x[2]]) {
if (y.f == x[1]) continue;
if (x[0]+y.s < dist[y.f][0].f) {
if (dist[y.f][0].s != x[2]) dist[y.f][1] = dist[y.f][0];
dist[y.f][0] = {x[0]+y.s,x[2]};
q.push({x[0]+y.s,x[2],y.f});
} else {
if (x[2] == dist[y.f][0].s) continue;
if (x[0]+y.s < dist[y.f][1].f) {
dist[y.f][1] = {x[0]+y.s,x[2]};
q.push({x[0]+y.s,x[2],y.f});
}
}
}
}
}
};
Dijkstra<MX> D;
int N,M,t,L;
dat d[MX][MX];
void init() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N >> M >> t >> L;
F0R(i,M) {
int A,B,C; cin >> A >> B >> C;
D.addEdge(A,B,C);
}
}
int main() {
init();
vector<T> path[MX];
FOR(i,1,N+1) {
for (pi j: D.adj[i]) {
D.gen({j.s,i,j.f});
/*if (i == 1) {
cout << "OOPS " << j.f << " " << i << " " << j.s << "\n";
cout << D.dist[2][0].f << " " << D.dist[2][0].s << "\n";
cout << D.dist[2][1].f << " " << D.dist[2][1].s << "\n";
}*/
FOR(k,1,N+1) if (k != i)
F0R(z,2) if (D.dist[k][z].f != INF)
path[k].pb({D.dist[k][z].f,j.f,D.dist[k][z].s});
}
FOR(k,1,N+1) if (k != i) {
/*if (i == 5 && k == 1) {
for (auto a: path[k]) cout << "HI " << a[0] << " " << a[1] << " " << a[2] << "\n";
} */
d[i][k] = dat({i,k},path[k]);
// for (auto a: d[i][k].besPath) cout << i << " " << k << " " << a[0] << " " << a[1] << " " << a[2] << "\n";
path[k].clear();
}
}
// for (auto a: d[5][1].besPath) cout << a[0] << " " << a[1] << " " << a[2] << "\n";
vl X(L); F0R(i,L) cin >> X[i];
F0R(i,t) {
int p,q; cin >> p >> q;
X[p-1] = q;
dat z = d[X[0]][X[1]];
FOR(i,2,L) z = comb(z,d[X[i-1]][X[i]]);
ll ans = INF;
for (auto a: z.besPath) ans = min(ans,a[0]);
//for (ll z: X) cout << z << " ";
//cout << "\n";
if (ans == INF) cout << "-1\n";
else cout << ans << "\n";
}
}
/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
153 ms |
125944 KB |
Output is correct |
| 2 |
Correct |
148 ms |
125980 KB |
Output is correct |
| 3 |
Incorrect |
151 ms |
126140 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
153 ms |
125944 KB |
Output is correct |
| 2 |
Correct |
148 ms |
125980 KB |
Output is correct |
| 3 |
Incorrect |
151 ms |
126140 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
153 ms |
125944 KB |
Output is correct |
| 2 |
Correct |
148 ms |
125980 KB |
Output is correct |
| 3 |
Incorrect |
151 ms |
126140 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
153 ms |
125944 KB |
Output is correct |
| 2 |
Correct |
148 ms |
125980 KB |
Output is correct |
| 3 |
Incorrect |
151 ms |
126140 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
