ソースコード
// g++ -std=c++11 a.cpp
#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<unordered_map>
#include<utility>
#include<cmath>
#include<random>
#include<cstring>
#include<queue>
#include<stack>
#include<bitset>
#include<cstdio>
#include<sstream>
#include<iomanip>
#include<assert.h>
#include<typeinfo>
#define loop(i,a,b) for(int i=a;i<b;i++)
#define rep(i,a) loop(i,0,a)
#define FOR(i,a) for(auto i:a)
#define pb push_back
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
#define show1d(v) rep(i,v.size())cout<<" "<<v[i];cout<<endl<<endl;
#define show2d(v) rep(i,v.size()){rep(j,v[i].size())cout<<" "<<v[i][j];cout<<endl;}cout<<endl;
using namespace std;
//kaewasuretyuui
typedef long long ll;
#define int ll
typedef int Def;
typedef pair<Def,Def> pii;
typedef vector<Def> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef pair<Def,pii> pip;
typedef vector<pip>vip;
//#define mt make_tuple
//typedef tuple<int,int,int> tp;
//typedef vector<tp> vt;
template<typename A,typename B>bool cmin(A &a,const B &b){return a>b?(a=b,true):false;}
template<typename A,typename B>bool cmax(A &a,const B &b){return a<b?(a=b,true):false;}
//template<class C>constexpr int size(const C &c){return (int)c.size();}
//template<class T,size_t N> constexpr int size(const T (&xs)[N])noexcept{return (int)N;}
const double PI=acos(-1);
const double EPS=1e-9;
Def inf = sizeof(Def) == sizeof(long long) ? 2e18 : 1e9+10;
int dx[]={0,1,0,-1};
int dy[]={1,0,-1,0};
class DIJ{
public:
struct edge{
int to,cost;
};
vector<vector<edge> >G;
int n;
vi d;//distance
DIJ(int size){
n=size;
G=vector<vector<edge> >(n);
}
void add_edge(int a,int b,int c){
edge e={b,c},ee={a,c};
G[a].pb(e);
G[b].pb(ee);
}
void dij(int k){
d=vi(n,-inf);
priority_queue<pii>q;
rep(i,k){
int a,b;cin>>a>>b;
d[a-1]=b+1;
q.push(pii(b+1,a-1));
}
while(!q.empty()){
pii p=q.top();
q.pop();
int pos=p.second,cost=p.first;
if(cost>d[pos])continue;
rep(i,G[pos].size()){
edge e=G[pos][i];
int to=e.to;
int nowcost=cost-e.cost;
if(nowcost>0&&nowcost>d[to]){
d[to]=nowcost;
q.push(pii(d[to],to));
}
}
}
int co=0;
rep(i,n)if(d[i]>0)co++;
cout<<co<<endl;
}
};
signed main(){
int n,m,k;
cin>>n>>m>>k;
DIJ dij(n);
while(m--){
int a,b,c;
cin>>a>>b>>c;
a--;b--;
dij.add_edge(a,b,c);
}
dij.dij(k);
}