L2-001 紧急救援
用堆优化的dijskstra，
#include <bits/stdc++.h>
using namespace std;
const int N = 505;
class Dist{
public:
int u;
int d;
Dist(int u_, int d_):u(u_),d(d_){}
bool operator <(const Dist& other)const{
return d > other.d;// 小顶堆
}
};
int pre[N];// 记录当前城市的上一个城市
int s;// 起点
void print(int x){// 输出路径
if(x == s) {
cout << s;
return;
}
print(pre[x]);
cout << " " << x;
}
void solve() {
int n, m, d; // s为起点 d为终点
cin >> n >> m >> s >> d;
int a[n + 1], w[n + 1];//a为每个城市的救援队数 w为能到达某城市的救援队数
vector<bool> vis(n + 1, false);
vector<Dist> g[n + 1];
for (int i = 0; i < n; ++i) {
cin >> a[i];
}
int num[n + 1];// 记录到达某座城市最短路径条数
w[s] = a[s];
num[s] = 1;
for (int i = 0; i < m; ++i) {
int u, v, w;
cin >> u >> v >> w;
g[u].push_back(Dist(v, w));
g[v].push_back(Dist(u, w));
}
priority_queue<Dist> q;
vector<int> dis(n + 1, INT_MAX);
dis[s] = 0;
q.push(Dist(s, 0));
while (!q.empty()) {
Dist cur = q.top();
q.pop();
int u = cur.u;
if (vis[u]) continue;
vis[u] = true;
for(auto& e : g[u]){
int v = e.u, d = e.d;
if(dis[v] > dis[u] + d){
dis[v] = dis[u] + d;
num[v] = num[u];
pre[v] = u;
w[v] = w[u] + a[v];
q.push(Dist(v, dis[v]));
}else if(dis[v] == dis[u] + d){
if(w[u] + a[v] > w[v]){
w[v] = w[u] + a[v];
pre[v] = u;
}
num[v] += num[u];
}
}
}
cout << num[d] << " " << w[d] << endl;
print(d);
}
int main() {
#ifdef ACM_LOCAL
freopen("data.in", "r", stdin);
// freopen("data.out", "w", stdout);
#endif
int T = 1;
// cin >> T;
while (T--) {
solve();
}
return 0;
}
