#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 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()
const int maxn = 1e5+10;
int n, q, idord[maxn], lf[maxn], rg[maxn], nx[maxn][25], pv[maxn][25];
void solve() {
cin >> n >> q;
vector<pair<pair<int,int>,int>> ord;
for(int i = 1; i <= n; i++) {
int l, r; cin >> l >> r;
ord.pb(mp(mp(r,l),i));
lf[i] = l;
rg[i] = r;
cc.pb(lf[i]);
cc.pb(rg[i]);
}
sort(all(cc));
cc.erase(unique(all(cc)),cc.end());
for(int i = 1; i <= n; i++) {
lf[i] = upper_bound(all(cc),lf[i])-cc.begin();
rf[i] = upper_bound(all(cc),rg[i])-cc.begin();
}
// sort(all(ord));
for(int i = 1; i <= n; i++) {
nx[i][0] = 0;
for(int j = 1; j <= n; j++) {
if(j == i || !(lf[j] <= rg[i] && rg[i] <= rg[j]) || !(rg[j] > rg[i])) continue;
if(nx[i][0] == 0 || rg[j] > rg[nx[i][0]]) nx[i][0] = j;
}
pv[i][0] = 0;
for(int j = 1; j <= n; j++) {
if(j == i || !(lf[i] <= rg[j] && rg[j] <= rg[i]) || !(lf[j] < lf[i])) continue;
if(pv[i][0] == 0 || lf[j] < lf[pv[i][0]]) pv[i][0] = j;
}
// int l = i+1;
// int r = n;
// while(l <= r) {
// int mid = (l+r)/2;
// if(lf[mid] <= rg[i]) {
// nx[i][0] = mid;
// l = mid+1;
// }
// else {
// r = mid-1;
// }
// }
// cout << i << " " << nx[i][0] << " " << pv[i][0] << endl;
}
for(int j = 1; j <= 20; j++) {
for(int i = 1; i <= n; i++) {
nx[i][j] = nx[nx[i][j-1]][j-1];
pv[i][j] = pv[pv[i][j-1]][j-1];
}
}
while(q--) {
int s,e; cin >> s >> e;
int ans = 0;
for(int j = 20; j >= 0; j--) {
if(nx[s][j] != 0 && rg[nx[s][j]] < rg[e]) {
ans+= (1<<j);
s = nx[s][j];
}
}
for(int j = 20; j >= 0; j--) {
if(pv[e][j] != 0 && lf[pv[e][j]] > lf[s]) {
ans+= (1<<j);
e = pv[e][j];
}
}
if(s == e) {
cout << ans << endl;
}
else if(lf[e] <= rg[s] && rg[s] <= rg[e]) {
cout << ans+1 << endl;
}
else if(nx[s][0] != 0 && lf[e] <= rg[nx[s][0]] && rg[nx[s][0]] <= rg[e]) {
cout << ans+2 << endl;
}
else if(pv[e][0] != 0 && lf[pv[e][0]] <= rg[s] && rg[s] <= rg[pv[e][0]]) {
cout << ans+2 << endl;
}
else {
cout << "impossible" << endl;
}
}
}
int32_t main() {
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.in", "r", stdin);
// freopen("out.out", "w", stdout);
int tt = 1;
// cin >> tt;
while(tt--) {
solve();
}
}
Compilation message
events.cpp: In function 'void solve()':
events.cpp:26:9: error: 'cc' was not declared in this scope; did you mean 'sc'?
26 | cc.pb(lf[i]);
| ^~
| sc
events.cpp:29:14: error: 'cc' was not declared in this scope; did you mean 'sc'?
29 | sort(all(cc));
| ^~
events.cpp:12:16: note: in definition of macro 'all'
12 | #define all(x) x.begin(), x.end()
| ^
events.cpp:33:9: error: 'rf' was not declared in this scope; did you mean 'rg'?
33 | rf[i] = upper_bound(all(cc),rg[i])-cc.begin();
| ^~
| rg
