Copying is not permitted

#include<stdio.h>
#include<vector>
using namespace std;
int n,m,p;
typedef long long int ll;
typedef struct{
    int v;
    ll w;
}edge;
vector<edge> adj[40010];
int component[40010];
bool visited[40010];
pair<int,int> restricted[50010];

void dfs(int u,int c,ll cW){
    if(visited[u])return;
    component[u] = c;
    visited[u] = true;
    for(int i=0;i<adj[u].size();i++){
        int v = adj[u][i].v;
        ll w = adj[u][i].w;
        if(w < cW && !visited[v]){
            dfs(v,c,cW);
        }
    }
}

bool check(ll cW){ //return true if can't copying
    for(int i=1;i<=n;i++){
        component[i] = i;
        visited[i] = false;
    }
    for(int i=1;i<=n;i++){
        if(!visited[i]){
            dfs(i,i,cW);
        }
    }
    for(int i=0;i<p;i++){
        if(component[restricted[i].first] == component[restricted[i].second]){
            return false;
        }
    }
    return true;
}

int main(){
    scanf("%d %d %d",&n,&m,&p);
    ll maxW = -2e9;
    for(int i=0;i<m;i++){
        int u,v;
        ll w;
        scanf("%d %d %lld",&u,&v,&w);
        if(w > maxW)maxW = w;
        adj[u].push_back({v,w});
        adj[v].push_back({u,w});
    }
    for(int i=0;i<p;i++){
        scanf("%d %d",&restricted[i].first,&restricted[i].second);
    }
    if(check(maxW+1)){
        printf("-1");
        return 0;
    }
    ll l = 0 , r = maxW;
    ll ans = -2e9;
    while(l <= r){
        ll m = (l+r)/2;
        if(check(m)){
            if(m > ans)ans = m;
            l = m + 1;
        }else{
            r = m - 1;
        }
    }
    printf("%lld",ans);
    return 0;
}