#include <bits/stdc++.h> using namespace std; //#define int long long #define FOR(I, L, R) for(int I(L) ; I <= (int)R ; ++I) #define FOD(I, R, L) for(int I(R) ; I >= (int)L ; --I) #define FOA(I, A) for(auto &I : A) #define print(A,L,R) FOR(OK, L, R){if(A[OK]<=-oo / 10||A[OK]>=oo / 10)cout<<"- ";else cout<<A[OK]<<' ';}cout<<'\n'; #define prints(A) FOA(OK, A){cout<<OK<<' ';}cout << '\n'; #define printz(A,L,R) FOR(OK, 1, L){FOR(KO, 1, R){if(A[OK][KO]>-oo / 10&&A[OK][KO]<oo)cout<<A[OK][KO]<<' ';else cout << "- ";} cout << '\n';}cout << '\n'; #define fs first #define sd second #define ii pair<int,int> #define iii pair<int, ii> #define all(A) A.begin(), A.end() #define quickly ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define FILE "PAIR" const int N = 2e5 + 5; const int mod = 1e9 + 7; const int oo = 1e9; struct Modint{ int x; Modint(){x = 0;} Modint(int _x){ x = (_x % mod + mod) % mod; } inline Modint operator + (const Modint &other) const{ return (x + other.x) % mod; } inline Modint operator - (const Modint &other) const{ return (x - other.x + mod) % mod; } inline Modint operator * (const Modint &other) const{ return (1LL * x * other.x) % mod; } inline void operator += (const Modint &other){ *this = *this + other; } inline void operator -= (const Modint &other){ *this = *this - other; } inline void operator *= (const Modint &other){ *this = *this * other; } friend ostream& operator << (ostream& os, const Modint &t){ return os << t.x; } }; int n, m, q; ii edge[N]; int far[N]; bool check[N]; struct per{ int u, szu, hu, v, szv, hv; }; vector<per> st[N]; struct DSU{ int parent[N], sz[N]; bool h[N]; void build(){FOR(i, 1, n){parent[i] = i, sz[i] = 1;}} int found(int u){ return (parent[u] == u ? u : found(parent[u])); } bool wei(int u){ if(u == parent[u]){ return 0; } return (wei(parent[u]) ^ h[u]); } bool setting(int u, int v, int x){ if(u == v) return 1; int U = found(u); int V = found(v); if(sz[U] < sz[V]) swap(U, V); st[x].push_back({U, sz[U], h[U], V, sz[V], h[V]}); if(U != V){ if(wei(v) == wei(u)) h[V] ^= 1; parent[V] = U; sz[U] += sz[V]; return 1; } return wei(u) != wei(v); } void rollback(int x){ while(!st[x].empty()){ int u = st[x].back().u; int v = st[x].back().v; int szu = st[x].back().szu; int szv = st[x].back().szv; int hu = st[x].back().hu; int hv = st[x].back().hv; parent[u] = u; parent[v] = v; sz[u] = szu; sz[v] = szv; h[u] = hu; h[v] = hv; st[x].pop_back(); } } } dsu; void dnc(int l, int r, int optl, int optr){ if(l > r) return; int mid = (l + r) >> 1; int opt = m + 1; FOR(i, l, mid){ int u = edge[i].fs; int v = edge[i].sd; check[mid] &= dsu.setting(u, v, mid); } FOD(i, optr, optl){ int u = edge[i].fs; int v = edge[i].sd; if(dsu.setting(u, v, mid)){ opt = i; } else break; } far[mid] = opt; dsu.rollback(mid); FOD(i, optr, opt){ int u = edge[i].fs; int v = edge[i].sd; dsu.setting(u, v, mid); } dnc(l, mid - 1, optl, opt); dsu.rollback(mid); FOR(i, l, mid){ int u = edge[i].fs; int v = edge[i].sd; dsu.setting(u, v, mid); } dnc(mid + 1, r, opt, optr); dsu.rollback(mid); } signed main(){ quickly if(fopen(FILE".inp", "r")){ freopen(FILE".inp", "r", stdin); freopen(FILE".out", "w", stdout); } cin >> n >> m >> q; dsu.build(); FOR(i, 1, m) check[i] = 1; FOR(i, 1, m){ int u, v; cin >> u >> v; edge[i] = {u, v}; } check[0] = 1; dnc(1, m, 1, m); FOR(i, 1, m){ check[i] &= check[i - 1]; } FOD(i, m, 1){ int u = edge[i].fs; int v = edge[i].sd; if(dsu.setting(u, v, 0)){ far[0] = i; } else break; } while(q--){ int l, r; cin >> l >> r; if(check[l - 1] == 0){ cout << "YES\n"; } else if(far[l - 1] - r > 1){ cout << "YES\n"; } else{ cout << "NO\n"; } } }

Joker.cpp: In function 'int main()':
Joker.cpp:157:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  157 |                 freopen(FILE".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:158:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  158 |                 freopen(FILE".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~