Submission #748153

#	Time	Username	Problem	Language	Result	Execution time	Memory
748153		Dan4Life	Dancing Elephants (IOI11_elephants)	C++17	26 / 100	24 ms	3908 KiB

elephants

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define all(a) a.begin(),a.end()
const int mxN = (int)1.5e5+10;
const int INF = (int)1e9;
const int B = 200;
const int mxB = mxN/B+1;

set<int> pos[mxB+2];
int n, L, tim, *p;
unordered_map<int,int> b;
set<array<int,3>> bl[mxB+2];
 
void reUpd(int i){
    bl[i].clear();
    auto itr = end(pos[i]), stop = begin(pos[i]);
    while(itr!=stop){ itr--;
        auto itr2 = bl[i].lower_bound({*itr+L+1,-1,-1});
        if(itr2!=bl[i].end())
            bl[i].insert({*itr,1+(*itr2)[1],(*itr2)[2]});
        else bl[i].insert({*itr,1,*itr+L+1});
    }
}

int findBl(int x){
    for(int i = 0; i < mxB; i++){
        if(pos[i].empty()) return (i==0?i:i-1);
        if(*prev(end(pos[i])) < x) continue;
    }
}

void ins(int x, int i=-1){
    b[x]++; if(b[x]!=1) return;
    if(i==-1) i=findBl(x);
    pos[i].insert(x), reUpd(i);
}
 
void del(int x, int i=-1){
    b[x]--; if(b[x]) return;
    if(i==-1) i = findBl(x);
    pos[i].erase(x), reUpd(i);
}

void build(){
    vector<int> v; v.clear(); b.clear();
    for(int i = 0; i < mxB; i++) 
        pos[i].clear(), bl[i].clear();
    for(int i = 0; i < n; i++) v.push_back(p[i]);
    sort(all(v)); v.erase(unique(all(v)),end(v));
    for(int j = 0; auto u : v){
        b[u]++; pos[j].insert(u);
        if(pos[j].size() >= B) j++;
    }
    for(int i = 0; i < mxB; i++) reUpd(i);
    return;
    for(int i = 0; i < mxB; i++){
        if(pos[i].empty()) continue;
        cout << i << ": ";
        for(auto u : pos[i]) cout << u << " ";
        cout << "\n";
    }
}
 
void init(int N, int l, int X[]){
    n = N; L = l; p=X; build();
}
 
int update(int i, int y)
{
    del(p[i]); p[i]=y; ins(y);
    if((++tim)%B==0) build(); 
    int ans = 0, cur = 0;
    for(int i = 0; i < mxB; i++){
        auto itr = bl[i].lower_bound({cur,-1,-1});
        if(itr!=bl[i].end()) ans+=(*itr)[1], cur = (*itr)[2];
    }
    return ans;
}

Compilation message (stderr)

elephants.cpp: In function 'void build()':
elephants.cpp:52:20: warning: range-based 'for' loops with initializer only available with '-std=c++2a' or '-std=gnu++2a'
   52 |     for(int j = 0; auto u : v){
      |                    ^~~~
elephants.cpp: In function 'int findBl(int)':
elephants.cpp:32:1: warning: control reaches end of non-void function [-Wreturn-type]
   32 | }
      | ^

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 0 / 24
• Subtask 4: 0 / 47
• Subtask 5: 0 / 3