C++ :

#include <bits/stdc++.h>
using namespace std;
const int maxn = 100100;
int dis[maxn][2], n, m, q;
vector<int> g[maxn];
struct Node {
    int u, s;
    Node (int _u, int _s) { u = _u; s = _s; }
};
queue<Node> que;
bool inq[maxn][2];
void spfa() {
    memset(inq, 0, sizeof(inq));
    memset(dis, -1, sizeof(dis));
    dis[1][0] = 0;
    que.push(Node(1, 0));
    while (!que.empty()) {
        Node nd = que.front();
        que.pop();
        int u = nd.u, s = nd.s;
        inq[u][s] = false;
        int sz = g[u].size();
        for (int i = 0; i < sz; i ++) {
            int v = g[u][i];
            if (dis[v][s^1] == -1 || dis[v][s^1] > dis[u][s] + 1) {
                dis[v][s^1] = dis[u][s] + 1;
                if (!inq[v][s^1]) {
                    inq[v][s^1] = true;
                    que.push(Node(v, s^1));
                }
            }
        }
    }
}
int main() {
    cin >> n >> m >> q;
    while (m --) {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    spfa();
    if (g[1].size() == 0) {
        while (q --) puts("No");
    }
    else {
        while (q --) {
            int a, L;
            cin >> a >> L;
            puts( dis[a][L%2] != -1 && dis[a][L%2] <= L ? "Yes" : "No" );
        }
    }
    return 0;
}