#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
typedef long long ll;
typedef long double ld;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef juggernaut
#define printl(args...) printf(args)
#else
#define printl(args...) 0
#endif
int n,q;
pair<int,int>a[100005];
bool cmp(pair<pair<int,int>,int>l,pair<pair<int,int>,int>r){
if(l.fr.sc==r.fr.sc)return l.fr.fr<r.fr.fr;
return l.fr.sc<r.fr.sc;
}
int lf[100005];
pair<pair<int,int>,int>b[100005];
const int inf=1e9;
int pos[100005];
int up[100005][20];
vector<int>g[100005];
int depth[100005];
void dfs(int v,int p){
up[v][0]=p;
depth[v]=depth[p]+1;
for(int i=1;i<19;i++)up[v][i]=up[up[v][i-1]][i-1];
for(int to:g[v])dfs(to,v);
}
int main(){
scanf("%d%d",&n,&q);
for(int i=1;i<=n;i++)scanf("%d%d",&a[i].fr,&a[i].sc);
for(int i=1;i<=n;i++)b[i]=make_pair(a[i],i);
sort(b+1,b+1+n,cmp);
for(int i=1;i<=n;i++)pos[b[i].sc]=i;
for(int i=1;i<=n;i++){
int l=1,r=i;
while(l<r){
int mid=(l+r)>>1;
if(b[i].fr.fr<=b[mid].fr.sc)r=mid;
else l=mid+1;
}
lf[i]=l;
if(lf[i]==l){
lf[i]=0;
if(i<n&&b[i+1].fr.fr<=b[i].fr.sc&&b[i].fr.sc<=b[i+1].fr.sc)lf[i]=i+1;
}
g[pos[lf[i]]].push_back(pos[i]);
}
dfs(0,0);
while(q--){
int x,y;
scanf("%d%d",&x,&y);
if(x==y){
puts("0");
continue;
}
if(a[y].fr<=a[x].sc&&a[x].sc<=a[y].sc){
puts("1");
continue;
}
swap(x,y);
if(depth[x]<depth[y])puts("impossible");
else{
int dist=depth[x]-depth[y];
for(int i=19;i>=0;i--)if(dist>>i&1)x=up[x][i];
if(x==y)printf("%d\n",dist);
else puts("impossible");
}
}
}
Compilation message
events.cpp: In function 'int main()':
events.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
40 | scanf("%d%d",&n,&q);
| ~~~~~^~~~~~~~~~~~~~
events.cpp:41:28: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
41 | for(int i=1;i<=n;i++)scanf("%d%d",&a[i].fr,&a[i].sc);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
events.cpp:62:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
62 | scanf("%d%d",&x,&y);
| ~~~~~^~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
2644 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
2644 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
2644 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
2644 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
130 ms |
20932 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
2644 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
