Submission #1083242

#TimeUsernameProblemLanguageResultExecution timeMemory
1083242Math4Life2020Ancient Books (IOI17_books)C++17
Compilation error
0 ms0 KiB
// Source: https://usaco.guide/general/io #include <bits/stdc++.h> using namespace std; using ll = long long; using pii = pair<ll,ll>; int triv(int N1) { for (ll i=0;i<N1;i++) { int *a0 = ask((int)i); if ((a0[0]+a0[1])==0) { return i; } } return -1; } map<ll,pii> pts; ll N; ll gm; ll ans = -1; vector<bool> asked; ll process(ll x) { if (!asked[x]) { int *a0 = ask((int)x); pts[x]={a0[0],a0[1]}; asked[x]=1; } ll S = pts[x].first+pts[x].second; if (S==0) { return x; } if (S<gm) { ll y = -1; if (x>0 && !asked[x-1]) { y=max(y,process(x-1)); } if (x<(N-1) && !asked[x+1]) { y=max(y,process(x+1)); } return y; } return -1; } void query(ll a, ll b) { if ((a+1)==b) { return; } if (pts[a].first==pts[b].first) { return; } ll c = (a+b)/2; ans=max(ans,process(c)); if (ans!=-1) { return; } auto A1 = pts.find(a); A1++; query(a,(*A1).first); auto B1 = pts.find(b); B1--; query((*B1).first,b); } int find_best(int N0) { N=N0; gm=0; ans = -1; pts.clear(); asked.clear(); for (ll i=0;i<N;i++) { asked.push_back(0); } if (N<=5000) { return triv(N); } ll r = (N-1)/500; for (ll i=1;i<=500;i++) { int *a0 = ask((int)(i*r)); asked[i*r]=1; pts[i*r]={a0[0],a0[1]}; } for (auto A: pts) { pii p0 = A.second; gm = max(gm,p0.first+p0.second); } for (auto A: pts) { ll v = process(A.first); if (v!=-1) { return v; } } if (process(0)!=-1) { return 0; } if (process(N-1)!=-1) { return (N-1); } auto A = pts.begin(); auto B=A; B++; do { pii pa = (*A).second; pii pb = (*B).second; if ((pa.first+pa.second+pb.first+pb.second)==(2*gm)) { query((*A).first,(*B).first); if (ans != -1) { return ans; } } A++; B++; } while (B != pts.end()); return -1; }

Compilation message (stderr)

books.cpp: In function 'int triv(int)':
books.cpp:9:13: error: 'ask' was not declared in this scope
    9 |   int *a0 = ask((int)i);
      |             ^~~
books.cpp: In function 'll process(ll)':
books.cpp:25:13: error: 'ask' was not declared in this scope
   25 |   int *a0 = ask((int)x);
      |             ^~~
books.cpp: In function 'int find_best(int)':
books.cpp:78:13: error: 'ask' was not declared in this scope
   78 |   int *a0 = ask((int)(i*r));
      |             ^~~