CSU 1808 地铁

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-6;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
template <class T>
inline void read(T &x)
{
    char c = getchar(); x = 0;while(!isdigit(c)) c = getchar();
    while(isdigit(c)) { x = x * 10 + c - ‘0‘; c = getchar();  }
}

const LL INF=(LL)1e17;
const int maxn=200010;
struct Edge
{
    int u,v,c; LL t;
    int nx;
}e[maxn];
int h[maxn],sz;
int n,m;
LL ans[maxn];

void add(int u,int v,int c,LL t)
{
    e[sz].u=u; e[sz].v=v; e[sz].c=c; e[sz].t=t;
    e[sz].nx=h[u]; h[u]=sz++;
}

struct Node
{
    int p,id;
    LL dis;
    Node(int P,int ID,LL DIS) { dis=DIS, p=P, id=ID; }
    bool operator < (const Node &a) const {
        if(dis==a.dis&&p==a.p) return id>a.id;
        if(dis==a.dis) return p>a.p;
        return dis>a.dis;
    }
};

struct X
{
    int p,id;
    X (int P,int ID) { p=P, id=ID; }
    bool operator < (const X &a) const {
        if(p==a.p) return id>a.id;
        return p>a.p;
    }
};

LL ABS(LL a) { if(a>=0) return a; return -a; }

void dij()
{
    map<X,LL>f; priority_queue<Node>Q;
    Q.push(Node(1,0,0));
    for(int i=1;i<=n;i++) ans[i]=INF; ans[1]=0;

    while(!Q.empty())
    {
        Node top=Q.top(); Q.pop();
        ans[top.p]=min(ans[top.p],top.dis);
        if(top.dis>f[X(top.p,top.id)]) continue;

        for(int i=h[top.p];i!=-1;i=e[i].nx)
        {
            LL COST;
            if(top.p==1) COST=0;
            else COST=ABS((LL)e[i].c-(LL)top.id);

            LL pp=f[X(e[i].v,e[i].c)];
            if((pp==0&&e[i].v!=1)||top.dis+COST+e[i].t<pp)
            {
                f[X(e[i].v,e[i].c)]=top.dis+COST+e[i].t;
                Q.push(Node(e[i].v,e[i].c,top.dis+COST+e[i].t));
            }
        }
    }
}

int main()
{
    while(~scanf("%d%d",&n,&m))
    {
        memset(h,-1,sizeof h); sz=0;
        for(int i=1;i<=m;i++)
        {
            int u,v,c; LL t;
            scanf("%d%d%d%lld",&u,&v,&c,&t);
            add(u,v,c,t); add(v,u,c,t);
        }
        dij();
        cout<<ans[n]<<endl;
    }
    return 0;
}