//≽^•⩊•^≼
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mod = 998244353;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n, q; cin >> n >> q;
vector<array<int, 2>> v(n);
vector<vector<array<int, 2>>> qu(n);
vector<array<int, 20>> gh(n);
vector<int> id(n), ans(q, -1);
for(auto &[i, l]: v) cin >> i >> l;
iota(id.begin(), id.end(), 0);
sort(id.begin(), id.end(), [&](int i, int j){
return v[i] < v[j];
});
vector<int> el;
for(int i=0; i<20; i++){
for(int l=0; l<n; l++){
gh[l][i]=-1;
}
}
for(int i=0; i<n; i++){
/* for(auto i: el) cout<<v[i][0]<<" "<<v[i][1]<<"\n";
cout<<"\n";*/
if(el.size()){
int s=-1;
for(int j=17; j>=0; j--){
int tmp = (s+(1<<j));
if(tmp >= el.size()) continue;
if(v[el[tmp]][1]<v[id[i]][0]) s=tmp;
}
s++;
if(s<el.size() && v[el[s]][1]>=v[id[i]][0]&&v[el[s]][1]<=v[id[i]][1]){
gh[id[i]][0]=el[s];
}
}
if(el.size() && v[el.back()][1]<=v[id[i]][1]){
while(el.size()&&v[el.back()][0]==v[id[i]][0])el.pop_back();
el.push_back(id[i]);
}
else if(!el.size())el.push_back(id[i]);
}
el.clear();
for(int i=1; i<20; i++){
for(int l=0; l<n; l++){
if(gh[l][i-1]==-1) gh[l][i]=-1;
else gh[l][i] = gh[gh[l][i-1]][i-1];
}
}
auto c = [&](int x, int y){
return !(v[y][1] <= v[x][1]&&v[y][1]>=v[x][0])&&v[x][0]>=v[y][0];
};
auto a = [&](int x, int y){
if(v[x][0]==v[y][0]) return v[y][1] > v[x][1];
return v[x][0] > v[y][0];
// return !(v[y][1] <= v[x][1]&&v[y][1]>=v[x][0]);
};
auto func =[&](int x, int y)->int{
int h=0;
if(x==y) return 0;
// cout<<x<<" "<<gh[x][0];
for(int j=9; j>=0; j--){
if(gh[x][j]!=-1&&c(gh[x][j], y)&&(j==0||gh[x][j]!=gh[x][j-1])&& a(x, gh[x][j])){
h+=(1<<j); x=gh[x][j];
//j++;
}
}
if(x!=gh[x][0]&&gh[x][0]!=-1)x = gh[x][0], h++;
// cout<<v[x][1]<<" "<<v[y][1]<<"\n";
if((v[y][1] <= v[x][1]&&v[y][1]>=v[x][0])) return h+(x==y?0:1);
return -1LL;
};
while(q--){
int x, y; cin >> x >> y;
x--; y--;
int h = func(y, x);
if(h==-1) cout<<"impossible";
else cout<<h;
cout<<"\n";
}
}
Compilation message
events.cpp: In function 'int main()':
events.cpp:45:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
45 | if(tmp >= el.size()) continue;
| ~~~~^~~~~~~~~~~~
events.cpp:50:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
50 | if(s<el.size() && v[el[s]][1]>=v[id[i]][0]&&v[el[s]][1]<=v[id[i]][1]){
| ~^~~~~~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Incorrect |
70 ms |
23404 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
604 KB |
Output is correct |
4 |
Correct |
1 ms |
604 KB |
Output is correct |
5 |
Incorrect |
1 ms |
604 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
604 KB |
Output is correct |
4 |
Correct |
1 ms |
604 KB |
Output is correct |
5 |
Incorrect |
1 ms |
604 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
348 KB |
Output is correct |
2 |
Correct |
0 ms |
348 KB |
Output is correct |
3 |
Correct |
1 ms |
604 KB |
Output is correct |
4 |
Correct |
1 ms |
604 KB |
Output is correct |
5 |
Incorrect |
1 ms |
604 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
70 ms |
23504 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
344 KB |
Output is correct |
2 |
Incorrect |
70 ms |
23404 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |