Implementation
P_3_Hitchhiking_Fun.cpp
C++
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int inf = 1e9;
const long long INF = 1e17; //❄️
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int n, m; cin >> n >> m;
vector<vector<pair<int, int>>> adj(n + 1);
for (int i = 0; i < m; i++) {
int u, v, w; cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
vector<int> cnt(n + 1, inf);
deque<int> dq;
cnt[1] = 0;
dq.push_front(1);
while (!dq.empty()) {
int u = dq.front(); dq.pop_front();
for (auto [v, d] : adj[u]) {
int nd = cnt[u] + d;
if (nd < cnt[v]) {
cnt[v] = nd;
if (d == 0) {
dq.push_front(v);
} else {
dq.push_back(v);
}
}
}
}
if (cnt[n] == inf) {
cout << -1 << '\n';
return 0;
}
vector<int> step(n + 1, inf);
queue<int> q;
step[1] = 0;
q.push(1);
while (!q.empty()) {
int u = q.front(); q.pop();
for (auto[v, d] : adj[u]) {
if (cnt[u] + d == cnt[v]) {
if (step[u] + 1 < step[v]) {
step[v] = + step[u] + 1;
q.push(v);
}
}
}
}
cout << cnt[n] << " " << step[n] << '\n';
return 0;
}