#include <bits/stdc++.h>
using namespace std;
typedef long long llo;
#define a first
#define b second
#define pb push_back
#define endl '\n'
int aa[100001];
int bb[100001];
int par[100001][20];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n,q;
cin>>n>>q;
vector<pair<int,pair<int,int>>> ss;
for(int i=0;i<n;i++){
cin>>aa[i]>>bb[i];
ss.pb({aa[i],{0,i}});
ss.pb({bb[i],{1,i}});
}
sort(ss.begin(),ss.end());
set<pair<int,int>> cur;
for(auto j:ss){
if(j.b.a==0){
cur.insert({bb[j.b.b],j.b.b});
}
else{
par[j.b.b][0]=-1;
if(cur.size()){
auto jj=cur.end();
jj--;
if((*jj).a>j.a){
int no=(*jj).b;
par[j.b.b][0]=no;
}
}
}
}
/* for(int i=0;i<n;i++){
cout<<par[i][0]<<",";
}
cout<<endl;*/
for(int j=1;j<20;j++){
for(int i=0;i<n;i++){
if(par[i][j-1]==-1){
par[i][j]=-1;
}
else{
par[i][j]=par[par[i][j-1]][j-1];
}
}
}
for(int ii=0;ii<q;ii++){
int l,r;
cin>>l>>r;
l--;
r--;
if(l==r){
cout<<0<<endl;
continue;
}
if(bb[r]<bb[l]){
cout<<"impossible"<<endl;
continue;
}
int su=0;
int cur=l;
for(int j=19;j>=0;j--){
if(par[cur][j]>=0){
if(bb[par[cur][j]]<bb[r]){
su+=(1<<j);
cur=par[cur][j];
}
}
}
if(par[cur][0]>=0){
if(aa[r]<=bb[cur] and bb[r]>=bb[cur]){
su++;
cur=par[cur][0];
//cout<<cur<<":"<<bb[cur]<<endl;
}
else{
cur=par[cur][0];
//cout<<cur<<",,"<<endl;
//if(par[cur][0]>=0){
if(aa[r]<=bb[cur] and bb[r]>=bb[cur]){
su+=2;
}
else{
su=-1;
}
//}
//else{
// su=-1;
//}
// if(par[cur][1]>=0)
}
}
else{
//su=-1;
cout<<"impossible"<<endl;
continue;
}
if(su==-1){
cout<<"impossible"<<endl;
continue;
}
cout<<su<<endl;
}
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
96 ms |
16520 KB |
Output is correct |
3 |
Correct |
101 ms |
16516 KB |
Output is correct |
4 |
Correct |
128 ms |
16472 KB |
Output is correct |
5 |
Correct |
112 ms |
16588 KB |
Output is correct |
6 |
Correct |
109 ms |
16572 KB |
Output is correct |
7 |
Correct |
106 ms |
16692 KB |
Output is correct |
8 |
Correct |
93 ms |
16948 KB |
Output is correct |
9 |
Correct |
96 ms |
17080 KB |
Output is correct |
10 |
Correct |
127 ms |
16948 KB |
Output is correct |
11 |
Incorrect |
113 ms |
16948 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
468 KB |
Output is correct |
4 |
Correct |
1 ms |
468 KB |
Output is correct |
5 |
Incorrect |
1 ms |
468 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
468 KB |
Output is correct |
4 |
Correct |
1 ms |
468 KB |
Output is correct |
5 |
Incorrect |
1 ms |
468 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
0 ms |
340 KB |
Output is correct |
3 |
Correct |
1 ms |
468 KB |
Output is correct |
4 |
Correct |
1 ms |
468 KB |
Output is correct |
5 |
Incorrect |
1 ms |
468 KB |
Output isn't correct |
6 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
118 ms |
16484 KB |
Output is correct |
2 |
Correct |
100 ms |
16508 KB |
Output is correct |
3 |
Correct |
129 ms |
16520 KB |
Output is correct |
4 |
Correct |
95 ms |
17048 KB |
Output is correct |
5 |
Correct |
129 ms |
16912 KB |
Output is correct |
6 |
Correct |
117 ms |
16692 KB |
Output is correct |
7 |
Correct |
109 ms |
16720 KB |
Output is correct |
8 |
Correct |
104 ms |
16780 KB |
Output is correct |
9 |
Correct |
67 ms |
15888 KB |
Output is correct |
10 |
Correct |
122 ms |
16308 KB |
Output is correct |
11 |
Correct |
96 ms |
16068 KB |
Output is correct |
12 |
Correct |
110 ms |
16328 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
96 ms |
16520 KB |
Output is correct |
3 |
Correct |
101 ms |
16516 KB |
Output is correct |
4 |
Correct |
128 ms |
16472 KB |
Output is correct |
5 |
Correct |
112 ms |
16588 KB |
Output is correct |
6 |
Correct |
109 ms |
16572 KB |
Output is correct |
7 |
Correct |
106 ms |
16692 KB |
Output is correct |
8 |
Correct |
93 ms |
16948 KB |
Output is correct |
9 |
Correct |
96 ms |
17080 KB |
Output is correct |
10 |
Correct |
127 ms |
16948 KB |
Output is correct |
11 |
Incorrect |
113 ms |
16948 KB |
Output isn't correct |
12 |
Halted |
0 ms |
0 KB |
- |