#include <bits/stdc++.h> #define task "testing" #define ll long long #define multitest 0 using namespace std; struct Edge { int u, v; }; struct Queries { int l, r; }; const int N = 2e5; int n, m, q; Edge E[N+5]; Queries Q[N+5]; bitset<N+5> res; namespace sub12 { const int sN = 2e3; int dsu[2*sN+5]; int flip(int v) { return v+(v <= n ? n : -n); } void reset() { fill(dsu+1, dsu+2*n+1, -1); } int root(int v) { return dsu[v] < 0 ? v : dsu[v] = root(dsu[v]); } void unite(int u, int v) { if ((u = root(u)) == (v = root(v))) return; if (dsu[u] > dsu[v]) swap(u, v); dsu[u] += dsu[v], dsu[v] = u; } bool connect(int u, int v) { return root(u) == root(v); } bool check() { return max({n, m, q}) <= sN; } bool qry(int l, int r) { reset(); for (int x = 1; x < l; x++) { unite(E[x].u, flip(E[x].v)); unite(flip(E[x].u), E[x].v); } for (int x = m; x > r; x--) { unite(E[x].u, flip(E[x].v)); unite(flip(E[x].u), E[x].v); } for (int x = 1; x <= n; x++) { if (connect(x, flip(x))) return 1; } return 0; } void solve() { for (int x = 1; x <= q; x++) { if (qry(Q[x].l, Q[x].r)) res.set(x); } } } namespace sub34 { const int L = 200; int dsu[2*N+5], rt[L+5], mxL; bool check() { mxL = 0; for (int x = 1; x <= q; x++) { mxL = max(mxL, Q[x].l); } return mxL <= L; } int flip(int v) { return v+(v <= n ? n : -n); } void reset() { fill(dsu+1, dsu+2*n+1, -1); } int root(int v) { return dsu[v] < 0 ? v : dsu[v] = root(dsu[v]); } bool connect(int u, int v) { return root(u) == root(v); } bool unite(int u, int v) { if ((u = root(u)) == (v = root(v))) return 0; if (dsu[u] > dsu[v]) swap(u, v); dsu[u] += dsu[v], dsu[v] = u; return connect(u, flip(u)) || connect(v, flip(v)); } void calc(int l) { reset(); bool ex = 0; for (int x = 1; x < l && !ex; x++) { ex |= unite(E[x].u, flip(E[x].v)); ex |= unite(flip(E[x].u), E[x].v); } if (ex) rt[l] = m+1; for (int r = m; r > l && !ex; r--) { ex |= unite(E[r].u, flip(E[r].v)); ex |= unite(flip(E[r].u), E[r].v); if (ex) rt[l] = r; } } void solve() { for (int x = min(m, mxL); x >= 1; x--) calc(x); for (int x = 1; x <= q; x++) { if (Q[x].r < rt[Q[x].l]) res.set(x); } } } namespace sub56 { struct Data { bool cyc; int u, v, szu, szv, t; }; bool cyc = 0; stack<Data> saved; int sz[2*N+5], par[2*N+5], rt[N+5], t = 0; int flip(int v) { return v+(v <= n ? n : -n); } int root(int v) { return par[v] == v ? v : root(par[v]); } bool connect(int u, int v) { return root(u) == root(v); } void unite(int u, int v) { if ((u = root(u)) == (v = root(v))) return; if (sz[u] < sz[v]) swap(u, v); saved.push({cyc, u, v, sz[u], sz[v], t}); sz[u] += sz[v], par[v] = u, t++; cyc |= connect(u, flip(u)); cyc |= connect(v, flip(v)); } void roll(int T) { while (!saved.empty()) { Data cur = saved.top(); if (cur.t == T) break; saved.pop(); cyc = cur.cyc; sz[par[cur.u] = cur.u] = cur.szu; sz[par[cur.v] = cur.v] = cur.szv; } t = T; } void dnc(int l, int r, int optL, int optR) { if (l > r) return; int mid = (l+r)/2, cur = t; for (int x = optL+1; x < mid; x++) { unite(E[x].u, flip(E[x].v)); unite(flip(E[x].u), E[x].v); } rt[mid] = optR; while (rt[mid] >= mid && !cyc) { rt[mid]--; unite(E[rt[mid]].u, flip(E[rt[mid]].v)); unite(flip(E[rt[mid]].u), E[rt[mid]].v); } roll(cur); for (int x = optR-1; x >= rt[mid]; x--) { unite(E[x].u, flip(E[x].v)); unite(flip(E[x].u), E[x].v); } dnc(l, mid-1, optL, rt[mid]); roll(cur); dnc(mid+1, r, rt[mid], optR); } void solve() { for (int x = 2*n; x >= 1; x--) { sz[x] = 1, par[x] = x; } dnc(1, m, 0, m+1); for (int x = 1; x <= q; x++) { if (Q[x].r < rt[Q[x].l]) res.set(x); } } } void flo(int ID) { cin >> n >> m >> q; for (int x = 1; x <= m; x++) { cin >> E[x].u >> E[x].v; } for (int x = 1; x <= q; x++) { cin >> Q[x].l >> Q[x].r; } if (sub12::check()) sub12::solve(); else if (sub34::check()) sub34::solve(); else sub56::solve(); for (int x = 1; x <= q; x++) { cout << (res.test(x) ? "YES\n" : "NO\n"); } } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } int TCS = 1, ID = 1; if (multitest) { cin >> TCS; } while (TCS--) flo(ID++); return 0; }

Joker.cpp: In function 'int main()':
Joker.cpp:281:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  281 |                 freopen(task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:282:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  282 |                 freopen(task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~