CF20C Dijkstra?（dij，含链式前向星存图模板）

Dijkstra? - 洛谷

dij模板题，没啥好说的

#include 
using namespace std;
#define ll long long
const int N = 200005;
int n, m, st, en;
ll dist[N];  //距离数组
int pre[N];  //前驱
int head[N], tot;
//结构体数组edge存边，edge[i]表示第i条边,
//head[i]存以i为起点的第一条边(在edge中的下标)
struct e{
    int next, to;
    ll w;
} edge[N*4];
void add(int u, int v, ll w){
    edge[tot].to = v;
    edge[tot].w = w;
    edge[tot].next = head[u];
    head[u] = tot++;
}
void init(){
    tot = 0;
    memset(head, -1 ,sizeof(head));
    memset(pre, -1, sizeof(pre));
}
struct node{
    int id;
    ll dis;
    bool operator< (const node& tmp)const{
        return dis > tmp.dis;
    }
};

priority_queue q;
void dij(){
    for(int i=0; i<=n; i++) dist[i] = 1e18;
    dist[st] = 0;
    node n1;
    n1.id = st, n1.dis = 0;
    q.push(n1);
    while(q.size()){
        int u = q.top().id; q.pop();
        for(int i=head[u]; i!=-1; i=edge[i].next){
            int v = edge[i].to;
            ll w = edge[i].w;
            if (dist[v] > dist[u] + w)
            {
                dist[v] = dist[u] + w;
                node n2;
                n2.id = v, n2.dis = dist[v];
                q.push(n2);
                pre[v] = u; //注意别忘了记录最优路径前驱
            }
        }
    }
}

vector path;
void getPath(){
    for(int i=en; i!=-1; i=pre[i]){
        path.push_back(i);
    }
}

int main(){
    cin >> n >> m;
    st = 1, en = n;
    int u, v; ll w;
    init();
    for(int i=1; i<=m; i++){
        cin >> u >> v >> w;
        add(u, v, w);
        add(v, u, w);
    }
    dij();
    if(dist[en] == 1e18){
        cout << -1 << 'n';
        return 0;
    }
    getPath();
    for(int i=path.size()-1; i>=0; i--){
        cout << path[i] << ' ';
    }
}