/* Author : Mychecksdead */
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define oset tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 2e5+10, F = 2147483646, K = 20;
struct Dsu {
vector<int> s;
vector<pair<int, int>> p;
vector<bool> bp;
Dsu(int n){
s.resize(n+1, 0);
p.resize(n+1);
bp.resize(n+1);
for(int i = 0; i <= n; ++i) p[i] = {i, 0}, bp[i] = 1;
}
pair<int, int> find_set(int v) {
if (v != p[v].first) {
int parity = p[v].second;
p[v] = find_set(p[v].first);
p[v].second ^= parity;
}
return p[v];
}
void merge(int a, int b){
pair<int, int> pa = find_set(a);
a = pa.first;
int x = pa.second;
pair<int, int> pb = find_set(b);
b = pb.first;
int y = pb.second;
if (a == b) {
if (x == y)
bp[a] = 0;
} else {
if (rank[a] < rank[b])
swap (a, b);
p[b] = make_pair(a, x^y^1);
bp[a] = bp[b] & bp[a];
if (rank[a] == rank[b])
++rank[a];
}
}
};
int n, m, q, l, r;
bool ok;
vector<pair<int, int>> g[N], edges;
bitset<M> vis, pos;
void dfs(int v, int p, bool c){
vis[v] = 1;
pos[v] = c;
for(auto k: g[v]){
int u = k.first;
if(l <= k.second && k.second <= r) continue;
if(u != p){
if(vis[u])
ok |= pos[v] == pos[u];
else
dfs(u, v, !c);
}
}
}
void solve(){
cin >> n >> m >> q;
for(int i = 0; i < m; ++i){
int u, v; cin >> u >> v;
g[u].pb({v, i + 1});
g[v].pb({u, i + 1});
edges.pb({u, v});
}
if(n <= 2000 && q <= 2000){
for(int i = 0; i < q; ++i){
cin >> l >> r;
vis = 0;
ok = 0;
for(int v = 1; v <= n; ++v) if(!ok && !vis[v]) dfs(v, v, 0);
if(ok) cout << "YES\n";
else cout << "NO\n";
}
}
else{
vector<pair<int, int>> queries[205];
vector<int> qq(q + 1);
for(int i = 1; i <= q; ++i){
cin >> l >> r;
queries[l].pb({r, i});
}
for(int i = 1; i <= 200; ++i){
if(queries[i].empty()) continue;
Dsu d(n);
ok = 0;
for(int j = 1; j < i; ++j){
int u = edges[j - 1].first, v = edges[j - 1].second;
d.merge(u, v);
ok |= !d.bp[d.find_set(u).first] | !d.bp[d.find_set(v).first];
}
sort(all(queries[i]), [&](const pair<int, int> &a, const pair<int, int> &b){
return a.first > b.first;
});
int cur = m;
for(auto k: queries[i]){
while(cur > k.first){
int u = edges[cur - 1].first, v = edges[cur - 1].second;
d.merge(u, v);
ok |= !d.bp[d.find_set(u).first] | !d.bp[d.find_set(v).first];
cur--;
}
qq[k.second] = ok;
}
}
for(int i = 1; i <= q; ++i) cout << (qq[i] ? "YES\n" : "NO\n");
}
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
cout << '\n';
}
return 0;
}
Compilation message
Joker.cpp: In member function 'void Dsu::merge(int, int)':
Joker.cpp:49:21: error: expected unqualified-id before '[' token
49 | if (rank[a] < rank[b])
| ^
Joker.cpp:53:21: error: expected unqualified-id before '[' token
53 | if (rank[a] == rank[b])
| ^
Joker.cpp:54:23: error: missing template arguments before '[' token
54 | ++rank[a];
| ^
Joker.cpp: In function 'int main()':
Joker.cpp:134:16: warning: unused variable 'aa' [-Wunused-variable]
134 | int T = 1, aa;
| ^~
