Implementation
Problem_3_Visiting_Grandma.cpp
C++
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int inf = 1e9;
const long long INF = 1e17; //❄️
const int mod = 1e6;
int main() {
ios::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
vector<vector<pair<int, int>>> adj(n + 1);
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
int c; cin >> c;
if (i == j) continue;
adj[i + 1].emplace_back(c, j + 1);
}
}
int m; cin >> m;
unordered_set<int> c;
for (int i = 0; i < m; i++) {
int k; cin >> k;
c.insert(k);
}
priority_queue<tuple<int, int, int>, vector<tuple<int, int, int>>, greater<tuple<int, int, int>>> pq;
pq.push({0, 1, c.count(1) ? 1 : 0});
vector<array<int, 2>> dist(n + 1, {inf, inf}), cnt(n + 1, {0, 0});
dist[1][c.count(1) ? 1 : 0] = 0;
cnt[1][c.count(1) ? 1 : 0] = 1;
while(!pq.empty()) {
auto[w, u, s] = pq.top(); pq.pop();
if (w > dist[u][s]) continue;
for (auto[wt, v] : adj[u]) {
int ns = s || (c.count(v) ? 1 : 0);
if (dist[v][ns] > w + wt) {
dist[v][ns] = w + wt;
cnt[v][ns] = cnt[u][s];
pq.push({dist[v][ns], v, ns});
} else if (dist[v][ns] == w + wt) {
cnt[v][ns] = (cnt[v][ns] + cnt[u][s]) % mod;
}
}
}
cout << dist[n][1] << " " << cnt[n][1] << '\n';
return 0;
}