L3-011 直捣黄龙 （dijkstra变形）_l3-011 直捣黄龙 测试点2

解题思路：使用优先队列优化的dijkstra算法

#include<bits/stdc++.h>
#define N 201
#define inf 0x3f3f3f3f
using namespace std;
string s1,s2,s3,s4;
int num[N],pre[N],dis[N],st,ed,cnt[N],rcnt[N],sr[N],n,vis[N];
map<string,int> s;
string a[N];
struct node
{
	int v,d;
	node()
	{
	}
	node(int v,int d):v(v),d(d)
	{
	}
};
vector<node> p[N];
struct node2
{
	int v,d;
	node2(){
	}
	node2(int v,int d):v(v),d(d){
	}
};
bool operator<(node2 a,node2 b)
{
	return a.d>b.d;
}
priority_queue<node2> q;
void dijkstra()
{
	q.push(node2(st,0));
	for(int i=0;i<n;i++) dis[i]=inf;
	dis[st]=0;rcnt[st]=1;
	node2 t;
	int u,w,v;
	while(!q.empty())
	{
		t=q.top();
		q.pop();
		u=t.v;w=t.d;
		if(vis[u]) continue;
		vis[u]=1;
		for(int i=0;i<p[u].size();i++)
		{
			v=p[u][i].v;
			if(dis[v]>w+p[u][i].d)
			{
				dis[v]=w+p[u][i].d;
				q.push(node2(v,dis[v]));
				sr[v]=sr[u]+num[v];
				rcnt[v]=rcnt[u];
				cnt[v]=cnt[u]+1;
				pre[v]=u;
			}else
			if(dis[v]==w+p[u][i].d)
			{
				rcnt[v]+=rcnt[u];
				if(cnt[v]<cnt[u]+1)
				{
					cnt[v]=cnt[u]+1;
					sr[v]=sr[u]+num[v];
					pre[v]=u;
				}else
				if(cnt[v]==cnt[u]+1)
				{
					if(sr[v]<sr[u]+num[v])
					{
						sr[v]=sr[u]+num[v];
						pre[v]=u;
					}
				}
			}	
		}
	}
}
stack<int> stk;
int main()
{
	//freopen("t.txt","r",stdin);
	int k,d;
	cin>>n>>k>>s1>>s2;
	s[s1]=0;a[0]=s1;
	for(int i=1;i<n;i++)
	{
		cin>>s3>>d;
		s[s3]=i;a[i]=s3;
		num[i]=d;
	}
	while(k--)
	{
		cin>>s3>>s4>>d;
		int u=s[s3],v=s[s4];
		p[u].push_back(node(v,d));
		p[v].push_back(node(u,d));
	}
	st=s[s1];
	ed=s[s2];
	pre[st]=-1;
	dijkstra();
	for(int i=ed;i!=-1;i=pre[i]) stk.push(i);
	cout<<a[stk.top()];
	stk.pop();
	while(!stk.empty())
	{
		cout<<"->"<<a[stk.top()];
		stk.pop();
	}
	cout<<endl;
	cout<<rcnt[ed]<<" "<<dis[ed]<<" "<<sr[ed];
	return 0;
 }