#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 dp[5005][5005];
int lf[5005];
pair<pair<int,int>,int>b[5005];
const int inf=1e9;
int pos[5005];
int main(){
scanf("%d%d",&n,&q);
for(int i=1;i<=n;i++)scanf("%d%d",&a[i].fr,&a[i].sc);
if(n<=5000){
for(int i=0;i<5005;i++)
for(int j=0;j<5005;j++)dp[i][j]=inf;
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;
}
for(int i=1;i<=n;i++){
dp[i][i]=0;
for(int j=i+1;j<=n;j++){
for(int k=1;k<j;k++)if(b[j].fr.fr<=b[k].fr.sc&&b[k].fr.sc<=b[j].fr.sc)umin(dp[i][j],dp[i][k]+1);
}
}
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;
}
if(dp[pos[x]][pos[y]]>=inf)puts("impossible");
else printf("%d\n",dp[pos[x]][pos[y]]);
}
return 0;
}
return 1;
}
Compilation message
events.cpp: In function 'int main()':
events.cpp:32:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
32 | scanf("%d%d",&n,&q);
| ~~~~~^~~~~~~~~~~~~~
events.cpp:33:28: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
33 | for(int i=1;i<=n;i++)scanf("%d%d",&a[i].fr,&a[i].sc);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
events.cpp:57:9: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
57 | scanf("%d%d",&x,&y);
| ~~~~~^~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
47 ms |
98228 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
58 ms |
98300 KB |
Output is correct |
| 2 |
Incorrect |
44 ms |
98248 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
58 ms |
98300 KB |
Output is correct |
| 2 |
Incorrect |
44 ms |
98248 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
58 ms |
98300 KB |
Output is correct |
| 2 |
Incorrect |
44 ms |
98248 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
21 ms |
1032 KB |
Execution failed because the return code was nonzero |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
47 ms |
98228 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
