Peli

input/code.cpp: In function 'pl bfs(const vvl&, ll, ll, ll, ll)':
input/code.cpp:28:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   28 |         auto [u, v] = q.front();
      |              ^
input/code.cpp:39:19: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   39 |                 if(x == b)
      |                   ^
input/code.cpp:21:8: warning: variable 'ans' set but not used [-Wunused-but-set-variable]
   21 |     pl ans = {-1, -1}, pre;
      |        ^~~

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector <ll> vl;
typedef vector <vl> vvl;
typedef pair <ll, ll> pl;
typedef vector <pl> vpl;
typedef vector <bool> vb;

const ll inf = 1e18;
const ll mod = 1e9 + 7;
const ll nmax = 1e6;

#define fi first
#define se second
#define mp make_pair
#define pb push_back

pl bfs(const vvl &g, ll a, ll b, ll k, ll n)
{
    pl ans = {-1, -1}, pre;
    queue <pair <ll, pl>> q;
    vpl val(n + 1, {-1, -1});
    val[a] = {0, -1};
    q.push({a, {0, -1}});
    while(!q.empty())
    {
        auto [u, v] = q.front();
        q.pop();
        for(auto x : g[u])
        {
            if(val[x].fi == -1 || val[x].se == -1)
            {
                pre = val[x];
                if(val[x].fi == -1 && v.se != -1)
                    val[x].fi = v.se + 1;
                if(val[x].se == -1 && v.fi != -1)
                    val[x].se = v.fi + 1;
                if(x == b)
                    if(k % 2 == 0)
                        if(val[x].fi != -1)
                            return val[x];
                        else;
                    else
                        if(val[x].se != -1)
                            return val[x];
                if(pre != val[x])
                    q.push({x, val[x]});
            }
        }
    }

    /*for(auto x : val)
        cerr << x.fi << "," << x.se << " ";*/

    return val[b];
}

/*4 5 6
1 2
2 3
1 3
2 4
3 4
1 2 2
1 4 1
1 4 5
2 2 1
2 2 2
3 4 8*/

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);

    ll n, m, q, i, a, b, k;
    pl ans;
    cin >> n >> m >> q;
    vvl g(n + 1);
    vpl minn(n + 1, {inf, inf});

    for(i = 0; i < m; i++)
    {
        cin >> a >> b;
        g[a].pb(b);
        g[b].pb(a);
    }

    while(q--)
    {
        cin >> a >> b >> k;
        ans = bfs(g, a, b, k, n);
        //cout << ans.fi << " " << ans.se << "\n";
        if(k % 2 == 0)
            if(ans.fi != -1 && ans.fi <= k)
                cout << "YES\n";
            else
                cout << "NO\n";
        else
            if(ans.se != -1 && ans.se <= k)
                cout << "YES\n";
            else
                cout << "NO\n";
    }

    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED