# https://vjudge.net/problem/Gym-101630J/origin

#include <iostream>
#include <cstdio>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cstring>
#define inf 2147483647000000
#define N 1000010
#define p(a) putchar(a)
#define For(i,a,b) for(register long long i=a;i<=b;++i)

using namespace std;
long long n,m,k,x,y,ans;
long long v[N],d[N];
bool vis[N];
deque<long long>q;
struct node{
long long n;
long long v;
node *next;
}*e[N];

inline void in(long long &x){
long long y=1;char c=getchar();x=0;
while(c<'0'||c>'9'){if(c=='-')y=-1;c=getchar();}
while(c<='9'&&c>='0'){ x=(x<<1)+(x<<3)+c-'0';c=getchar();}
x*=y;
}
inline void o(long long x){
if(x<0){p('-');x=-x;}
if(x>9)o(x/10);
p(x%10+'0');
}

inline void push(register long long x,register long long y,register long long v){
node *p;
p=new node();
p->n=y;
p->v=v;
if(e[x]==0)
e[x]=p;
else{
p->next=e[x]->next;
e[x]->next=p;
}
}

inline long long spfa(long long t){
For(i,0,n) vis[i]=0,d[i]=inf;
d[1]=0;
q.push_back(1);
while(!q.empty()){
x=q.front();q.pop_front();
vis[x]=1;
for(register node *i=e[x];i;i=i->next){
if(d[i->n]>d[x]+max((long long)0,i->v-t)){
d[i->n]=d[x]+max((long long)0,i->v-t);
if(!vis[i->n]){
vis[i->n]=1;
if(!q.empty()&&d[i->n]<d[q.front()]) q.push_front(i->n);
else q.push_back(i->n);
}
}
}

vis[x]=0;
}
return d[n];
}

signed main(){
in(n);in(m);in(k);
For(i,1,m){
in(x);in(y);in(v[i]);
push(x,y,v[i]);
push(y,x,v[i]);
}
ans=spfa(0);
For(i,1,m) ans=min(ans,spfa(v[i])+k*v[i]);
o(ans);
return 0;
}

posted @ 2020-03-25 21:24  WeiAR  阅读(121)  评论(0编辑  收藏