Language: C++

/*
これを入れて実行
g++ code.cpp
./a.out
 */
 
#include <iostream>
#include <stdio.h>
#include <vector>
#include <string>
#include <cstring>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <unordered_map>
#include <cmath>
#include <math.h>
#include <tuple>
#include <iomanip>
#include <bitset>
#include <functional>

#define all(x) (x).begin(),(x).end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
 
using namespace std;
typedef long long ll;
typedef long double ld;
 
int dy4[4] = {-1, 0, +1, 0};
int dx4[4] = {0, +1, 0, -1};
int dy8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};
 
const long long INF = 1LL << 62;
const ll MOD = 1e9 + 7;
 
bool greaterSecond(const pair<int, int>& f, const pair<int, int>& s){
    return f.second > s.second;
}
 
ll gcd(ll a, ll b){
	if (b == 0)return a;
	return gcd(b, a % b);
}
 
ll lcm(ll a, ll b){
    return a / gcd(a, b) * b;
}

ll conbinationMemo[100][100];

ll cmemoInit(){
    rep(i, 100){
        rep(j, 100){
            conbinationMemo[i][j] = -1;
        }
    }
}
 
ll nCr(ll n, ll r){
    if(conbinationMemo[n][r] != -1) return conbinationMemo[n][r];
    if(r == 0 || r == n){
        return 1;
    } else if(r == 1){
        return n;
    }
    return conbinationMemo[n][r] = (nCr(n - 1, r) + nCr(n - 1, r - 1));
}
 
ll nPr(ll n, ll r){
    r = n - r;
    ll ret = 1;
    for (ll i = n; i >= r + 1; i--) ret *= i;
    return ret;
}
 
//-----------------------ここから-----------
struct Edge{
    ll from;
    ll to;
    ll cost;
};
int main(void){
    ll n, m, l;
    cin >> n >> m >> l;
    vector<vector<Edge>> g(n);
    rep(i, m){
        ll a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        Edge tmp;
        tmp.from = a;
        tmp.to = b;
        tmp.cost = c;
        g[a].push_back(tmp);
        swap(tmp.from, tmp.to);
        g[b].push_back(tmp);
    }

    ll q;
    cin >> q;
    vector<pair<ll,ll>> qs(q);
    rep(i, q){
        ll s, t;
        cin >> s >> t;
        s--, t--;
        qs[i] = {s, t};
    }

    vector<vector<ll>> ans(n, vector<ll>(n, INF));

    rep(i, n){
        queue<pair<pair<ll,ll>, ll>> que;
        que.push({{i, 0}, l});

        vector<pair<ll,ll>> dist(n, {0, INF});

        while(!que.empty()){
            ll now = que.front().first.first;
            ll nowr = que.front().first.second;
            ll nowf = que.front().second;
            que.pop();
            rep(i, g[now].size()){
                Edge next = g[now][i];
                if(next.cost > nowf){
                    if(dist[next.to].second < nowr + 1 || ans[next.to].first > l - next.cost){
                        continue;
                    }
                    
                    ans[next.to] = {l - next.cost, nowr + 1};
                    que.push({{next.to, nowr + 1}, l - next.cost}); 
                } else {
                    if(dist[next.to].second < nowr || ans[next.to].first > nowf - next.cost){
                        continue;
                    }
                    dist[next.to] = {nowf - next.cost, nowr};
                    que.push({{next.to, nowr}, nowf - next.cost}); 
                }
            }
        }
        rep(j, n){
            ans[i][j] = dist[j].second;
        }
    }

    rep(i, q){
        ll s = qs[i].first;
        ll t = qs[i].second;
        cout << (ans[s][t]>=INF?-1:ans[s][t]) << endl;
    }
}

Compiler output:
a.cc: In function 'll cmemoInit()':
a.cc:62:1: warning: no return statement in function returning non-void [-Wreturn-type]
   62 | }
      | ^
a.cc: In function 'int main()':
a.cc:130:72: error: '__gnu_cxx::__alloc_traits<std::allocator<std::vector<long long int> >, std::vector<long long int> >::value_type' {aka 'class std::vector<long long int>'} has no member named 'first'
  130 |                     if(dist[next.to].second < nowr + 1 || ans[next.to].first > l - next.cost){
      |                                                                        ^~~~~
a.cc:137:68: error: '__gnu_cxx::__alloc_traits<std::allocator<std::vector<long long int> >, std::vector<long long int> >::value_type' {aka 'class std::vector<long long int>'} has no member named 'first'
  137 |                     if(dist[next.to].second < nowr || ans[next.to].first > nowf - next.cost){
      |                                                                    ^~~~~