#pragma GCC optimize("O3,unroll-loops") #include <bits/stdc++.h> using namespace std; #define int long long #define ll long long #define pb push_back #define pii pair<int,int> #define sz(v) (int)v.size() #define fi first #define se second #define INF 1223372036854775807 #define INF2 122337203 #define MOD 998244353 #define cint(x) int x;cin>>x; #define cinarr(a,n) int a[n];for (int i=0;i<n;i++) cin>>a[i]; #define coutarr(a) for (auto d:a)cout<<d<<" "; cout<<endl; #define coutarrD(a) for (auto d:a) cout<<d.fi<<","<<d.se<<" "; cout<<endl; #define BERKAY_TUP ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL) #define endl '\n' #define ld long double #define mid (start+end)/2 #define vvi vector<vector<int>> int t=1; int interactive=0; int usaco=0; int testCase=0; void solve(){ int n,q; cin>>n>>q; vector<pii> v; for (int i=0;i<n;i++){ int x,y; cin>>x>>y; v.pb({x,y}); } vector<int> edges[1023]; for (int i=0;i<n;i++){ for (int j=0;j<n;j++){ if (i==j) continue; if (v[j].se>=v[i].se && v[i].se>=v[j].fi) edges[i].pb(j); } } while (q--){ int a,b; cin>>a>>b; a--;b--; int dist[1023]; bool seen[1023]={}; for (int i=0;i<1023;i++) dist[i]=-1; queue<int> q; q.push(a); dist[a]=0; int y=30; while (!q.empty() && y--){ int c=q.front(); q.pop(); if (seen[c]) continue; seen[c]=true; for (int d:edges[c]){ if (dist[d]==-1){ q.push(d); dist[d]=dist[c]+1; } } } if (!seen[b]){ cout<<"impossible"<<endl; } else{ cout<<dist[b]<<endl; } } } int32_t main(){ BERKAY_TUP; if (usaco){ freopen("team.in", "r", stdin); freopen("team.out", "w", stdout); } if (!interactive){ #ifdef Local freopen("in.txt", "r", stdin); freopen("out2.txt", "w", stdout); //freopen("wormsort.out", "w", stdout); #endif } if (t==1) solve(); else{ cin>>t; while (t--){testCase++;solve();} } return 0; }

events.cpp: In function 'int32_t main()':
events.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen("team.in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
events.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen("team.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~