稀疏图_Dijkstra算法(系统堆优化)

#include
#include
#include
#include
using namespace std;

const int N=100010;

typedef pair PII;

int q[N],dist[N];
int h[N],e[N],ne[N],w[N],idx;
int n,m;

void add(int a, int b, int c)
{
    e[idx]=b, w[idx]=c, ne[idx]=h[a], h[a]=idx++;
}

int dijkstra()
{
    memset(dist, 0x3f, sizeof dist);
    dist[1]=0;
    
    //堆优化版优先队列
    priority_queue , greater> heap;//greater小顶堆
    heap.push({0,1});//first是距离，second是数字
    
    while(heap.size())
    {
        auto t=heap.top();//堆用的是top,队列用的是front
        heap.pop();
        
        //利用t更新数据
        int ver=t.second, distance=t.first;
        for(int i=h[ver];i!=-1;i=ne[i])
        {
            int j=e[i];
            if(dist[j]>distance+w[i])
            {
                dist[j]=distance+w[i];
                heap.push({dist[j],j});
            }
        }
    }
    
    if(dist[n]==0x3f3f3f3f) return -1;
    return dist[n];
    
}

int main()
{
    cin>>n>>m;
    
    memset(h, -1, sizeof h);
    
    while(m--)
    {
        int a,b,c;
        cin>>a>>b>>c;
        add(a,b,c);
    }
    
    cout<