Segcolt
0040981432
I am stupid, I made a struct that ordenates everything into a different way, but then I forgot to change the variables on the dijkstra loop to the correct order and ended up screwing everything... At least I'm sure I won't be doing this mistake again in the future.
143 lines
2.9 KiB
C++
143 lines
2.9 KiB
C++
/* Problem URL: https://cses.fi/problemset/task/1195 */
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#include <bits/stdc++.h>
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using namespace std;
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#define V vector
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#define rmin(a, b) a = min(a, b)
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#define rmax(a, b) a = max(a, b)
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#define rep(i, lim) for (size_t i = 0; i < (lim); i++)
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#define nrep(i, s, lim) for (size_t i = s; i < (lim); i++)
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#define repv(i, v) for (auto &i : (v))
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#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
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#define sortv(v) sort(v.begin(), v.end())
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#define all(v) (v).begin(), (v).end()
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using vi = vector<int>;
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using vvi = vector<vi>;
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using vvvi = vector<vvi>;
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using vvvvi = vector<vvvi>;
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using ll = long long;
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using vl = vector<ll>;
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using vvl = vector<vl>;
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using vvvl = vector<vvl>;
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using vvvvl = vector<vvvl>;
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template<class v>
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auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
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os << vec[0];
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for (size_t i = 1; i < vec.size(); i++) {
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os << ' ' << vec[i];
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}
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os << '\n';
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return os;
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}
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template<class v>
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auto operator>>(istream &is, vector<v> &vec)->istream& {
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for (auto &i : vec) {
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is >> i;
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}
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return is;
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}
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template<class v>
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auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
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for (auto &i : vec) {
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os << i[0];
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for (size_t j = 1; j < i.size(); j++) {
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os << ' ' << i[j];
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}
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os << '\n';
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}
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return os;
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}
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template<class v>
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auto operator>>(istream &is, vector<vector<v>> &vec)->istream& {
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for (auto &i : vec) {
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for (auto &j : i) {
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is >> j;
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}
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}
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return is;
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}
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struct node {
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public:
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int no;
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ll cost;
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int used;
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node(int no, long long cost, int used) : no(no), cost(cost), used(used) {}
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auto operator<(node &n) const->bool {
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return cost < n.cost;
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}
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auto operator>(node &n) const->bool {
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return cost > n.cost;
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}
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};
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vvl dist;
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V<V<pair<int, ll>>> graph;
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long long dijkstra(int n)
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{
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priority_queue<node, V<node>, greater<>> pq;
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pq.emplace(0, 0, 0);
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dist[0][0] = 0;
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dist[0][1] = 0;
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while (!pq.empty()) {
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auto [v, u, b] = pq.top(); pq.pop();
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if (dist[v][b] < u) {
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continue;
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}
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for (auto [n, c] : graph[v]) {
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if (u + c < dist[n][b]) {
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dist[n][b] = u + c;
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pq.emplace(n, dist[n][b], b);
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}
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if (b == 0 && u + (c / 2) < dist[n][1]) {
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dist[n][1] = u + (c / 2);
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pq.emplace(n, dist[n][1], 1) ;
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}
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}
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}
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return min(dist[n - 1][0], dist[n - 1][1]);
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}
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int main()
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{
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ios::sync_with_stdio(false);
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cin.tie(nullptr);
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int n, m;
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cin >> n >> m;
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dist.assign(n, vl(2, INT64_MAX));
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graph.resize(n);
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while (m--) {
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long long a, b, c;
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cin >> a >> b >> c;
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a--, b--;
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graph[a].emplace_back(b, c);
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}
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cout << dijkstra(n) << '\n';
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return 0;
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}
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