121 lines
3.2 KiB
C++
121 lines
3.2 KiB
C++
#include <iostream>
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#include <vector>
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#include <queue>
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#include <climits>
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#include <algorithm>
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using namespace std;
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const int INF = INT_MAX;
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struct Edge {
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int to;
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int time;
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Edge(int t, int w) : to(t), time(w) {}
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};
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struct Node {
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int station;
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int state; //0没用过，1用过了
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int time;
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Node(int s, int st, int t) : station(s), state(st), time(t) {}
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bool operator>(const Node& other) const {
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return time > other.time;
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}
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};
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int main() {
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int n, s, t;
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while (cin >> n >> s >> t) {
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int m;
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cin >> m;
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vector<vector<Edge>> bus(n + 1);
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for (int i = 0; i < m; i++) {
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int a, b, c;
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cin >> a >> b >> c;
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bus[a].push_back(Edge(b, c));
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bus[b].push_back(Edge(a, c));
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}
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int k;
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cin >> k;
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vector<vector<Edge>> metro(n + 1);
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for (int i = 0; i < k; i++) {
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int x, y, z;
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cin >> x >> y >> z;
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metro[x].push_back(Edge(y, z));
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metro[y].push_back(Edge(x, z));
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}
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vector<vector<int>> dp(n + 1, vector<int>(2, INF));
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//换乘点K
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vector<int> K_record(n + 1, INF);
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priority_queue<Node, vector<Node>, greater<Node>> pq;
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dp[s][0] = 0;
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pq.push(Node(s, 0, 0));
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while (!pq.empty()) {
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Node curr = pq.top();
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pq.pop();
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int u = curr.station;
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int state = curr.state;
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int time = curr.time;
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if (time > dp[u][state]) {
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continue;
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}
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for (const Edge& e : bus[u]) {
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int v = e.to;
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int new_time = time + e.time;
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if (new_time < dp[v][state]) {
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dp[v][state] = new_time;
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if (state == 1 && K_record[u] != INF) {
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K_record[v] = K_record[u];
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}
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pq.push(Node(v, state, new_time));
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} else if (new_time == dp[v][state] && state == 1 && K_record[u] != INF) {
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if (K_record[v] == INF) {
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K_record[v] = K_record[u];
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} else {
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K_record[v] = min(K_record[v], K_record[u]);
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}
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}
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}
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if (state == 0) {
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for (const Edge& e : metro[u]) {
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int v = e.to;
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int new_time = time + e.time;
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if (new_time < dp[v][1]) {
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dp[v][1] = new_time;
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K_record[v] = u;
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pq.push(Node(v, 1, new_time));
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} else if (new_time == dp[v][1]) {
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K_record[v] = min(K_record[v], u);
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}
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}
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}
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}
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int T = min(dp[t][0], dp[t][1]);
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cout << T << endl;
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if (dp[t][0] <= dp[t][1]) {
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cout << "no metro" << endl;
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} else {
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cout << K_record[t] << endl;
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}
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}
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return 0;
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}
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