Submission #1105724

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105724		azberjibiou	Counting Mushrooms (IOI20_mushrooms)	C++17	80.71 / 100	8 ms	968 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define pb push_back
#define lb lower_bound
#define gibon ios::sync_with_stdio(false); cin.tie(0);
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
typedef long long ll;
using namespace std;
const int mxN=505;
const int mxM=2200005;
const int mxK=61;
const int MOD=1e9+7;
const ll INF=1e18;
const int C=160;
const double P=1.05;
vector <int> A, B;
int cntA;
int idx=1;
void check_one(){
    int val=use_machine(vector <int>{0, idx});
    if(val==0) A.push_back(idx);
    else B.push_back(idx);
    idx++;
}
void check_two(){
    assert(A.size()>=2 || B.size()>=2);
    bool swp=false;
    if(A.size()<2){
        swp=true;
        swap(A, B);
    }
    int val=use_machine(vector <int> {A[0], idx, A[1], idx+1});
    if(val%2==1) B.push_back(idx+1);
    else A.push_back(idx+1);
    if(val>=2) B.push_back(idx);
    else A.push_back(idx);
    idx+=2;
    if(swp) swap(A, B);
}
void check_C(){
    bool swp=false;
    if(A.size()<B.size()){
        swp=true;
        swap(A, B);
    }
    vector <int> v;
    for(int i=0;i<A.size();i++){
        v.push_back(A[i]);
        v.push_back(idx+i);
    }
    int val=use_machine(v);
    int sz=A.size();
    //end element
    if(val%2==0) A.push_back(idx+sz-1);
    else B.push_back(idx+sz-1);
    //middle element
    if(swp) cntA+=val/2;
    else cntA+=sz-1-val/2;
    //maintain idx, A, B
    idx+=sz;
    if(swp) swap(A, B);
}
void check_end(int n){
    bool swp=false;
    if(A.size()<B.size()){
        swp=true;
        swap(A, B);
    }
    vector <int> v;
    for(int i=0;i<A.size();i++){
        v.push_back(A[i]);
        if(idx+i<n) v.push_back(idx+i);
    }
    int val=use_machine(v);
    int sz=A.size(), cnt_mid=min(n-idx, sz-1);
  	if(n==idx+sz){
      	if(val%2==0) A.push_back(idx+sz-1);
      	else B.push_back(idx+sz-1);
    }
    if(swp) cntA+=val/2;
    else cntA+=cnt_mid-val/2;
    if(swp) swap(A, B);
  	idx=n;
}
int count_mushrooms(int n) {
    A.push_back(0);
    check_one();
    if(n==2) return A.size();
    if(A.size()==1) check_one();
  	while(idx<n){
      if(n-idx<=max(A.size(), B.size())) check_end(n);
      else if(max(A.size(), B.size())*idx/max(1, (int)min(A.size(), B.size()))>P*C/226){
        check_C();
      }
      else check_two();
    }
    return A.size()+cntA;
}

Compilation message (stderr)

mushrooms.cpp: In function 'void check_C()':
mushrooms.cpp:51:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for(int i=0;i<A.size();i++){
      |                 ~^~~~~~~~~
mushrooms.cpp: In function 'void check_end(int)':
mushrooms.cpp:74:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |     for(int i=0;i<A.size();i++){
      |                 ~^~~~~~~~~
mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:95:15: warning: comparison of integer expressions of different signedness: 'int' and 'const long unsigned int' [-Wsign-compare]
   95 |       if(n-idx<=max(A.size(), B.size())) check_end(n);
      |          ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 80.7143 / 100