# 题意概括

给出一个无向图，让你走不同的路径，从1到n，路径长度之和不超过E，求最大路径条数。

k短路模板题。

# 代码

#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cstdlib>
#include <cmath>
using namespace std;
const int N=5005,M=200002;
const double Inf=1e300;
struct Gragh{
int cnt,y[M*2],nxt[M*2],fst[N],vis[N],q[N],n;
double z[M*2],dis[N];
void clear(int n_){
cnt=0,n=n_;
memset(fst,0,sizeof fst);
}
y[++cnt]=b,z[cnt]=c,nxt[cnt]=fst[a],fst[a]=cnt;
}
void spfa(int st){
for (int i=1;i<=n;i++)
dis[i]=Inf;
memset(vis,0,sizeof vis);
dis[st]=0,vis[q[tail=tail%qmod+1]=st]=1;
for (int i=fst[X];i;i=nxt[i])
if (dis[X]+z[i]<dis[Y=y[i]]){
dis[Y]=dis[X]+z[i];
if (!vis[Y])
vis[q[tail=tail%qmod+1]=Y]=1;
}
}
}
}yg,g;
const int S=2000000;
int id[S],heap_size;
double now[S];
double h(int x){return g.dis[x];}
double G(int x){return now[x]+h(id[x]);}
void heap_clear(){heap_size=0;}
bool heap_empty(){return heap_size==0;}
bool heap_cmp(int a,int b){return G(a)<G(b);}
void heap_down(){
for (int i=1,j=i<<1;j<=heap_size;i=j,j=i<<1){
j+=j<heap_size&&!heap_cmp(j,j+1);
if (heap_cmp(i,j))
break;
swap(id[i],id[j]),swap(now[i],now[j]);
}
}
void heap_up(){
for (int i=heap_size,j=i>>1;i>1;i=j,j=i>>1)
if (!heap_cmp(j,i))
swap(id[i],id[j]),swap(now[i],now[j]);
else
break;
}
void heap_pop(){
id[1]=id[heap_size];
now[1]=now[heap_size--];
heap_down();
}
void heap_push(int x,double nowdis){
id[++heap_size]=x;
now[heap_size]=nowdis;
heap_up();
}
int n,m;
double E;
int solve(){
int ans=0;
heap_clear();
heap_push(1,0);
while (!heap_empty()){
int x=id[1];
double nowdis=now[1];
heap_pop();
if (x==n){
if (nowdis>E)
return ans;
E-=nowdis;
ans++;
continue;
}
for (int i=yg.fst[x];i;i=yg.nxt[i]){
int y=yg.y[i];
heap_push(y,nowdis+yg.z[i]);
}
}
}
int main(){
scanf("%d%d%lf",&n,&m,&E);
g.clear(n),yg.clear(n);
for (int i=1;i<=m;i++){
int a,b;
double e;
scanf("%d%d%lf",&a,&b,&e);