#include <bits/stdc++.h>
using namespace std;
#define fileio() freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define sp " "
#define endl "\n"
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define N 400005
const int modulo = 1e9 + 7;
int ans[N], u[N], v[N], l[N], r[N], n, sz[N];
vector<int> root;
vector<pii> block[N];
int res[N], s;
int find(vector<int> &b, int node, int flag)
{
if (node < 0) return -(find(b, -node, flag));
if (node == b[node]) return node;
if (flag) return b[node] = find(b, b[node], flag);
return find(b, b[node], flag);
}
int64_t main()
{
fastio();
int m, q;
cin>>n>>m>>q;
root.resize(n + 5, 0);
while(s * s < m) s++;
for (int i = 1; i <= m; i++)
{
cin>>u[i]>>v[i];
}
int maks = 0;
for (int i = 1; i <= q; i++)
{
cin>>l[i]>>r[i];
block[l[i] / s].pb({r[i], i});
}
int it = 0;
for (int i = 0; i <= m / s + 1; i++)
{
for (int j = 1; j <= n; j++) root[j] = j, sz[j] = 1;
sort(block[i].rbegin(), block[i].rend());
stack<pii> sl, slz;
int last = m;
for (auto j : block[i])
{
while(!sl.empty())
{
root[sl.top().st] = sl.top().nd;
sl.pop();
sz[slz.top().st] = slz.top().nd;
slz.pop();
}
//cout<<j.nd<<sp<<l[j.nd]<<sp<<r[j.nd]<<endl;
while(last > r[j.nd])
{
int a = find(root, u[last], 1), b = find(root, v[last], 1);
if (a == b)
{
res[j.nd] = 1;
break;
}
else
{
if (sz[abs(a)] > sz[abs(b)]) swap(a, b);
if (a < 0) a *= -1, b *= -1;
sz[abs(b)] += sz[a];
root[a] = -b;
}
last--;
}
for (int k = 1; k < l[j.nd]; k++)
{
int a = find(root, u[k], 0), b = find(root, v[k], 0);
if (a == b)
{
res[j.nd] = 1;
break;
}
else
{
if (sz[abs(a)] > sz[abs(b)]) swap(a, b);
if (a < 0) a *= -1, b *= -1;
slz.push({abs(b), sz[abs(b)]});
sz[abs(b)] += sz[a];
sl.push({a, root[a]});
root[a] = -b;
}
}
}
}
for (int i = 1; i <= q; i++)
{
if (res[i]) cout<<"YES\n";
else cout<<"NO\n";
}
cerr<<"time taken : "<<(float)clock() / CLOCKS_PER_SEC<<" seconds\n";
}
Compilation message
Joker.cpp:28:1: error: '::main' must return 'int'
28 | int64_t main()
| ^~~~~~~
Joker.cpp: In function 'int main()':
Joker.cpp:41:6: warning: unused variable 'maks' [-Wunused-variable]
41 | int maks = 0;
| ^~~~
Joker.cpp:48:6: warning: unused variable 'it' [-Wunused-variable]
48 | int it = 0;
| ^~
