| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 876690 | vjudge1 | Cyberland (APIO23_cyberland) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
// #include "cyberland.h"
using namespace std;
typedef long long ll;
const int N = 2e5 + 1;
vector<pair<int, int>> g[N];
double d[N][31];
double solve(int n, int m, int k, int h, std::vector<int> x, std::vector<int> y, std::vector<int> c, std::vector<int> arr)
{
for (int i = 0; i < n; i++)
{
for(int j = 0;j <= k;j++){
d[i][j] = 1e15;
}
g[i].clear();
}
for (int i = 0; i < m; i++)
{
g[x[i]].push_back({y[i], c[i]});
g[y[i]].push_back({x[i], c[i]});
}
queue<int> q;
vector<int> can(n,0);
can[0] = 1;
q.push(0);
while(!q.empty()){
int v = q.front();
q.pop();
for(auto [to,w]:g[v]){
if(to == h || can[to]) continue;
q.push(to);
can[to] = 1;
}
}
vector<int> vv(1, 0);
set<pair<double,pair<int,int>>> st;
for (int j = 0; j < n; j++)
{
if (!arr[j] && can[j])
{
st.insert({0,{0,j}});
d[j][0] = 0;
vv.push_back(j);
}
}
while(!st.empty()){
auto [col,v] = (*st.begin()).second;
st.erase({d[v][col],{col,v}});
// cout << v << ' ' << col << ' ' << d[v][col] << '\n';
for(auto [to,w]:g[v]){
if(col + 1 <= k && d[to][col + 1] > (d[v][col] + w) / 2 && arr[to] == 2){
st.erase({d[to][col + 1],{col + 1,to}});
d[to][col + 1] = (d[v][col] + w) / 2;
st.insert({d[to][col + 1],{col + 1,to}});
}
if(d[to][col] > d[v][col] + w){
st.erase({d[to][col],{col,to}});
d[to][col] = d[v][col] + w;
st.insert({d[to][col],{col,to}});
}
}
}
double res = 1e15;
for(int i = 0;i <= 30;i++){
res = min(res,d[h][i]);
}
if(res == 1e15) res = -1;
return res;
}
int main() {
int T;
assert(1 == scanf("%d", &T));
while (T--){
int N,M,K,H;
assert(4 == scanf("%d %d %d\n%d", &N, &M, &K, &H));
std::vector<int> x(M);
std::vector<int> y(M);
std::vector<int> c(M);
std::vector<int> arr(N);
for (int i=0;i<N;i++)
assert(1 == scanf("%d", &arr[i]));
for (int i=0;i<M;i++)
assert(3 == scanf("%d %d %d", &x[i], &y[i], &c[i]));
printf("%.12lf\n", solve(N, M, K, H, x, y, c, arr));
}
}