#include <bits/stdc++.h>
using namespace std;
int n, m, q;
int u[200005], v[200005];
int rmin[200005];
pair<int, int> t[200005];
int sz[200005];
bool bip[200005];
int cnt_bad;
int curi;
struct ura
{
int tip;///0 pentru p1.first != p2.first, 1 pentru celalalt
int idx = 0, x = 0, y = 0;
bool bipant = false;
};
vector<ura> op;
pair<int, int> par(int x)
{
int ugabuga = 0;
int s1 = 0;
while (t[x].first != x)
{
ugabuga++;
if (ugabuga >= 1000)
assert(false);
s1 += t[x].second;
x = t[x].first;
}
return make_pair(x, s1);
}
void join(int idx, int x, int y)
{
//cout << idx << ' ' << x << ' ' << y << endl;
pair<int,int> p1 = par(x);
pair<int,int> p2 = par(y);
//cout << x << ' ' << y << endl;
if (p1.first != p2.first)
{
if (sz[p1.first] < sz[p2.first])
swap(p1, p2);
//cout << "c1" << endl;
t[p2.first] = {p1.first, (1 + p1.second + p2.second) % 2};
//sz[x] += sz[y];
/*ura aux;
aux.tip = 0;
aux.idx = idx, aux.x = x, aux.y = y;
aux.bipant = bip[x];*/
/*if (bip[x] == false and bip[y] == false){
cnt_bad--;}
if (bip[y] == false)
bip[x] = false;*/
//op.push_back(aux);
}
else
{
/*ura aux;
aux.tip = 1;
aux.idx = idx;
aux.x = x;
aux.y = y;
aux.bipant = bip[x];*/
if (p1.second % 2 == p2.second % 2 and bip[x] == true)
{
//cout << "cmon" << p1.first << endl;
//bip[x] = false;
cnt_bad++;
}
//op.push_back(aux);
}
}
void und(ura uf)
{
//cout << "und" << uf.idx << endl;
if (uf.tip == 0)
{
if (bip[uf.y] == false and uf.bipant == false)
cnt_bad++;
bip[uf.x] = uf.bipant;
sz[uf.x] -= sz[uf.y];
t[uf.y] = {uf.y, 0};
}
else
{
if (bip[uf.x] != uf.bipant)
cnt_bad--;
bip[uf.x] = uf.bipant;
}
}
bool cmp(ura A, ura B)
{
if ((A.idx < curi and B.idx >= curi) or (A.idx >= curi and B.idx < curi))
return A.idx < B.idx;
else if (A.idx < curi)
return A.idx < B.idx;
else
return A.idx > B.idx;
}
void undo(int idx)
{
//cout << "u" << idx << endl;
vector<ura> cur;
int cate = 0;
while (true)
{
cur.push_back(op.back());
op.pop_back();
cate++;
if (cur.back().idx == idx)
break;
}
while (cate != 0 and !op.empty())
{
cur.push_back(op.back());
op.pop_back();
cate--;
}
for (auto it : cur)
und(it);
sort(cur.begin(), cur.end(), cmp);
for (auto it : cur)
if (it.idx != idx)
join(it.idx, u[it.idx], v[it.idx]);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin >> n >> m >> q;
for (int i = 1; i <= m; i++)
cin >> u[i] >> v[i];
for (int i = 1; i <= n; i++)
{
t[i] = {i, 0};
sz[i] = 1;
bip[i] = true;
}
/*for (int i = 1; i <= m; i++)
join(i, u[i], v[i]);
//cout << cnt_bad << endl;
if (cnt_bad == 0)
{
for (int i = 1; i <= q; i++)
{
int x, y;
cin >> x >> y;
cout << "NO\n";
}
return 0;
}
int r = 0;
for (int i = 1; i <= m; i++)
{
curi = i;
while (r < m and cnt_bad > 0)
{
r++;
undo(r);
}
if (cnt_bad != 0)
{
rmin[i] = m + 1;
continue;
}
rmin[i] = r;
join(i, u[i], v[i]);
}
//for (int i = 1; i <= m; i++)
// cout << rmin[i] << ' ';
//cout << endl;
for (int i = 1; i <= q; i++)
{
int x, y;
cin >> x >> y;
if (rmin[x] > y)
cout << "YES\n";
else
cout << "NO\n";
}*/
rmin[1] = 1;
for (int i = m; i >= 1; i--)
{
join(i, u[i], v[i]);
if (cnt_bad != 0)
{
rmin[1] = i;
break;
}
}
for (int i = 1; i <= q; i++)
{
int x, y;
cin >> x >> y;
if (y < rmin[x])
cout << "YES\n";
else
cout << "NO\n";
}
return 0;
}
/**
deci teoretic daca bag elementele de la 1 la N, apoi fac two pointers-ul, o sa cam am queue-like undoing pe DSU, pe care tin si ceva de bipartit
**/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Runtime error |
23 ms |
6372 KB |
Execution killed with signal 6 |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
348 KB |
Output is correct |
| 2 |
Correct |
0 ms |
348 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
348 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
