| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1045251 | Lobo | Joker (BOI20_joker) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
using namespace std;
const long long inf = 1e18 + 10;
const int inf1 = 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const int maxn = 2e5+10;
const int B = 2e5+10;
int n, m, q, col[maxn], colc[2*maxn], ansl[maxn];
vector<int> g[maxn], gc[2*maxn];
pair<int,int> edg[maxn];
bool okcol;
void dfscol(int u) {
for(auto v : g[u]) {
if(col[v] == -1) {
col[v] = (col[u]^1);
dfscol(v);
}
else if(col[v] != (col[u]^1)) {
okcol = 0;
}
}
}
bool okcolc;
void dfscolc(int u) {
for(auto v : gc[u]) {
if(colc[v] == -1) {
colc[v] = (colc[u]^1);
dfscolc(v);
}
else if(colc[v] != (colc[u]^1)) {
okcolc = 0;
}
}
}
void solve() {
cin >> n >> m >> q;
for(int i = 1; i <= m; i++) {
int u,v;
cin >> u >> v;
edg[i] = mp(u,v);
}
int bLl = 0;
int bLr = min(m+1,B-1);
int bRl = 1;
int bRr = min(m+1,B);
while(bLl != m+1 BLl <= 1) {
for(int i = 1; i <= n; i++) {
g[i].clear();
col[i] = -1;
}
for(int i = 1; i <= bLl-1; i++) {
int u = edg[i].fr;
int v = edg[i].sc;
g[u].pb(v);
g[v].pb(u);
}
for(int i = bRr+1; i <= m; i++) {
int u = edg[i].fr;
int v = edg[i].sc;
g[u].pb(v);
g[v].pb(u);
}
int cntcol = 0;
okcol = 1;
for(int i = 1; i <= n; i++) {
if(col[i] == -1) {
colc[cntcol] = -1;
colc[cntcol+1] = -1;
col[i] = cntcol;
cntcol = cntcol+2;
dfscol(i);
}
}
if(okcol == 0) {
bRl = min(m+1,bRr+1);
bRr = min(m+1,bRl+B-1);
continue;
}
int L = bLl;
int R = bRl;
while(L <= bLr and R <= bRr) {
// cout << L << " " << R << endl;
vector<int> verts;
for(int i = bLl; i <= L; i++) {
if(i == 0 or i == m+1) continue;
int u = edg[i].fr; verts.pb(u);
int v = edg[i].sc; verts.pb(v);
gc[col[u]].pb(col[v]);
gc[col[v]].pb(col[u]);
}
for(int i = R; i <= bRr; i++) {
if(i == 0 or i == m+1) continue;
int u = edg[i].fr; verts.pb(u);
int v = edg[i].sc; verts.pb(v);
gc[col[u]].pb(col[v]);
gc[col[v]].pb(col[u]);
}
okcolc = 1;
for(auto i : verts) {
if(colc[col[i]] == -1) {
colc[col[i]] = 0;
// if(R == 9) cout << i << " " << col[i] << endl;
dfscolc(col[i]);
}
}
if(okcolc == 1) {
ansl[L] = R;
L++;
}
else {
R++;
}
for(auto i : verts) {
colc[col[i]] = -1;
gc[col[i]].clear();
}
}
bLl = min(m+1,L);
bLr = (min(m+1,bLl+B-1));
bRl = min(m+1,R);
bRr = min(m+1,bRl+B-1);
}
for(int i = 1; i <= q; i++) {
int l,r;
cin >> l >> r;
if(ansl[l-1] <= r+1) {
cout << "NO" << endl;
}
else {
cout << "YES" << endl;
}
}
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
int tt = 1;
// cin >> tt;
while(tt--) {
solve();
}
}