Submission #343775

#TimeUsernameProblemLanguageResultExecution timeMemory
343775AmineWeslatiDancing Elephants (IOI11_elephants)C++14
100 / 100
8380 ms8424 KiB
//Never stop trying #ifndef LOCAL #pragma GCC optimize ("Ofast") #pragma GCC optimization ("O3") #pragma GCC optimization ("unroll-loops") #endif #include "bits/stdc++.h" using namespace std; #define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0) typedef long long ll; typedef string str; typedef double db; typedef long double ld; typedef pair<int, int> pi; #define fi first #define se second typedef vector<int> vi; typedef vector<pi> vpi; typedef vector<str> vs; typedef vector<ld> vd; #define pb push_back #define eb emplace_back #define sz(x) (int)x.size() #define all(x) begin(x), end(x) #define rall(x) rbegin(x), rend(x) #define endl "\n" #define FOR(i,a,b) for (int i = (a); i < (b); ++i) #define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i) const int MOD = 1e9 + 7; //998244353 const ll INF = 1e18; const int MX = 150000+100; const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up template<class T> using V = vector<T>; template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; } template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; } ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up //constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x)) mt19937 rng(chrono::system_clock::now().time_since_epoch().count()); //mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count()); ll random(ll a, ll b){ return a + rng() % (b - a + 1); } #ifndef LOCAL #define cerr if(false) cerr #endif #define dbg(x) cerr << #x << " : " << x << endl; #define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl; #define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl; #define here() cerr << "here" << endl; void IO() { #ifdef LOCAL freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout); #endif } #ifndef LOCAL #include "elephants.h" #endif int N,K,C,L; vi X(MX),B(MX),vec[500],J(MX),T(MX); void process(int b){ int j=sz(vec[b]); ROF(i,0,sz(vec[b])){ int lim=X[vec[b][i]]+L; while(j && X[vec[b][j-1]]>lim) j--; J[vec[b][i]]=1; if(j!=sz(vec[b])) J[vec[b][i]]=J[vec[b][j]]+1; T[vec[b][i]]=X[vec[b][i]]+L; if(j!=sz(vec[b])) T[vec[b][i]]=T[vec[b][j]]; } } void init(int N, int L, int P[]){ ::N=N; ::L=L; C=ceil(sqrt(N)); if(C==1) C=N; FOR(i,0,N) X[i]=P[i]; int cur_b=-1; K=0; FOR(i,0,N){ if(i%C==0) cur_b++; vec[cur_b].pb(i); B[i]=cur_b; } K=cur_b+1; FOR(i,0,K) process(i); } int solve(){ int cur_b=0,i=0,ans=0; while(1){ ans+=J[vec[cur_b][i]]; int lim=T[vec[cur_b][i]]; cur_b++; while(cur_b<=K-1 && !(lim<X[vec[cur_b].back()])){ cur_b++; } if(cur_b==K) break; int nxt; int l=0,r=sz(vec[cur_b])-1; while(l<=r){ int m=(l+r)/2; if(X[vec[cur_b][m]]>lim){ nxt=m; r=m-1; } else l=m+1; } i=nxt; } return ans; } int cnt_upd=0; int update(int p, int x){ X[p]=x; if(N==1) return 1; //replacing in the new bucket FOR(i,0,sz(vec[B[p]])) if(vec[B[p]][i]==p){ vec[B[p]].erase(vec[B[p]].begin()+i); process(B[p]); break; } FOR(i,0,K) if(!vec[i].empty()){ bool put=false; if(x<=X[vec[i][0]] && (!i || x>=X[vec[i-1].back()])){ vec[i].insert(vec[i].begin(),p); put=true; } else if(x>=X[vec[i].back()] && (i==K-1 || x<=X[vec[i+1][0]])){ vec[i].insert(vec[i].end(),p); put=true; } else if(x>=X[vec[i][0]] && x<X[vec[i].back()]){ FOR(j,0,sz(vec[i])-1) if(x>=X[vec[i][j]] && x<=X[vec[i][j+1]]){ vec[i].insert(vec[i].begin()+j+1,p); put=true; break; } } if(put){ B[p]=i; process(i); break; } } cnt_upd++; //rebuilding if(cnt_upd%(C-1)==0){ vi order; FOR(i,0,K) for(auto x: vec[i]) order.pb(x); int cur_b=-1; FOR(i,0,K) vec[i].clear(); FOR(i,0,N){ if(i%C==0) cur_b++; vec[cur_b].pb(order[i]); B[order[i]]=cur_b; } FOR(i,0,K) process(i); } return solve(); } #ifdef LOCAL int main() { boost; IO(); int N,L; cin>>N>>L; int X[N]; FOR(i,0,N) cin>>X[i]; init(N,L,X); int Q; cin>>Q; while(Q--){ int i,x; cin>>i>>x; cout << update(i,x) << endl; } return 0; } #endif /* Careful!!! .Array bounds .Infinite loops .Uninitialized variables / empty containers .Multisets are shit Some insights: .Binary search .Graph representation .Write brute force code .Change your approach */

Compilation message (stderr)

elephants.cpp:4: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    4 | #pragma GCC optimization ("O3")
      | 
elephants.cpp:5: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    5 | #pragma GCC optimization ("unroll-loops")
      | 
elephants.cpp: In function 'int solve()':
elephants.cpp:107:28: warning: 'nxt' may be used uninitialized in this function [-Wmaybe-uninitialized]
  107 |         ans+=J[vec[cur_b][i]];
      |                            ^
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