模板 Djkstra+链式前向星+堆优化

模板 Dijkstra+链式前向星+堆优化

#include
#include
#include
#include
#include
#define inf 0x3f3f3f3f
using namespace std;
struct Edge{
    int nex,to,w;
}edge[1000005];
int head[100005];
bool vis[100005];
int cnt=0;
int dis[100005];
int n;
inline void add(int u,int v,int w){
    edge[cnt].to=v;
    edge[cnt].w=w;
    edge[cnt].nex=head[u];
    head[u]=cnt++;
}
inline void read(int&x) {
    int f=1;x=0;char c=getchar();
    while(c>'9'||c<'0') {if(c=='-') f=-1;c=getchar();}
    while(c>='0'&&c<='9') {x=(x<<3)+(x<<1)+c-48,c=getchar();}
    x=x*f;
}

typedef pair<int, int> P;

void dij(int s){
    priority_queue
vector
,greater
 >q;
    memset(vis,0,sizeof vis);
    memset(dis,0x3f,sizeof dis);
    dis[s] = 0;
    q.push(P(0,s));
    while (!q.empty()){
        P p = q.top();
        q.pop();
        int u = p.second;
        if(vis[u])continue;
        vis[u] = 1;
        for(int i = head[u];~i;i=edge[i].nex){
            int v = edge[i].to;
            int w = edge[i].w;
            if(dis[v]>dis[u]+w&&!vis[v]){
                dis[v] = dis[u]+w;
                q.push(P(dis[v],v));
            }
        }
    }

}
int main()
{
    int m;
        scanf("%d%d",&n,&m);
        cnt=0;
        memset(head,-1,sizeof head);
        int u,v,w;
        for(int i=1;i<=m;i++){
            read(u),read(v),read(w);
            add(u,v,w);
        }
        dij(1);
    if(dis[n]>=inf){
        printf("-1\n");
    }
    else{
        printf("%d\n",dis[n]);
    }
    return 0;
}
/*
 3
 5 5
 1 2 6
 2 3 4
 2 4 5
 4 5 6
 1 5 1
 */