Peli

#include <bits/stdc++.h>

#define all(x) begin(x),end(x)
#define fi first
#define se second

using namespace std;
using ll = long long;
using pic = pair<int, char>;
using pii = pair<int, int>;

const int N = 2525;

int ans[N][N][2];
bool vis[N][2];

vector<int> adj[N];

void solve() {
    int n, m, q;
    cin >> n >> m >> q;

    memset(ans, 0x3f, sizeof ans);
    for (int i = 0; i < m; ++i) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for (int i = 1; i <= n; ++i) {
        queue<pii> bfs;
        memset(vis, 0, sizeof vis);
        ans[i][i][0] = 0;
        vis[i][0] = 1;
        bfs.push({i, 0});
        while (bfs.size()) {
            auto p = bfs.front();
            bfs.pop();
            for (int v : adj[p.fi]) if (!vis[v][(p.se & 1) ^ 1]) {
                vis[v][(p.se & 1) ^ 1] = 1;
                ans[i][v][(p.se & 1) ^ 1] = p.se+1;
                bfs.push({v, p.se+1});
            }
        }
    }

    while (q--) {
        int a, b, x;
        cin >> a >> b >> x;
        cout << (ans[a][b][x & 1] <= x ? "YES" : "NO") << '\n';
    }
}

int main() {
    cin.tie(0) -> sync_with_stdio(0);

    solve();

    return 0;
}

Test 1

Group: 1, 2

Verdict: ACCEPTED

Test 2

Group: 1, 2

Verdict: ACCEPTED

Test 3

Group: 2

Verdict: ACCEPTED

Test 4

Group: 1, 2

Verdict: ACCEPTED

Test 5

Group: 1, 2

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 1, 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED