Submission #724908

#	Time	Username	Problem	Language	Result	Execution time	Memory
724908		MohamedAliSaidane	Counting Mushrooms (IOI20_mushrooms)	C++14	92.62 / 100	10 ms	440 KiB

mushrooms

#include<bits/stdc++.h>
#include "mushrooms.h"
#include<ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef vector<pii> vpi;

#define ff first
#define ss second
#define pb push_back
#define all(x) (x).begin(),(x).end()

const ll MOD = 1e9 + 7, INF = 1e18;
ll mod(ll x, ll m = MOD) {return (x + m) % m;}

int N;
string S;
/*
int use_machine(vi v)
{
    int rep = 0;
    for(int i = 0; i < (int)(v.size()) - 1; i++)
        rep += (S[v[i]] != S[v[i + 1]]);
    return rep;
}
*/
int count_mushrooms(int n)
{
    char c = 'A', d= 'B';
    int a = 0, b = 1;
    int u = use_machine({0, 1});
    if(n == 2)
        return 2 - u;
    int last = 1;
    if(u == 1)
    {
        last = 2;
        if(use_machine({0, 2}))
        {
            a=  2;
            swap(c, d);

        }
        else
            b = 2;
    }
    vi A = {a, b};
    vi B;
    for(int j = 0; j <= last; j++)
        if(j != a && j != b)
            B.pb(j);
    int sza = (int)(A.size()), szb = (int)(B.size());
    int SQ  =  85;
    for(int i = last + 1; max(sza, szb) < SQ && max(sza, szb) * max(sza, szb) < n; i+= 2)
    {
        if(i == n -1)
        {
            last = i;
            if(use_machine({a, i}))
                B.pb(i);
            else
                A.pb(i);
        }
        else
        {
            last = i + 1;
            u = use_machine({a, i, b, i + 1});
            if(u == 1)
            {
                A.pb(i); B.pb(i + 1);
            }
            else if(u == 0)
            {
                A.pb(i); A.pb(i + 1);
            }
            else if(u == 2)
            {
                A.pb(i + 1);
                B.pb(i);
            }
            else
            {
                B.pb(i); B.pb(i + 1);
            }
        }
        sza = (int)(A.size());
        szb = (int)(B.size());
    }
    if(sza < szb)
    {
        swap(c, d);
        swap(A, B);
        swap(sza, szb);
    }
    int cnt = szb;
    int flag = 0;
    int Bloc = sza;
    for(int j = last + 1; j < n; j += Bloc)
    {
        vi v;
        Bloc = min(n - j, sza);
        for(int k = 0; k < Bloc; k++)
        {
            v.pb(A[k]);
            v.pb(j + k);
        }
        int r = use_machine(v);
        cnt += (r + 1)/2;
        if(r & 1)
            B.pb(j + Bloc - 1);
        else
            A.pb(j + Bloc - 1);
        sza = (int)(A.size());
        szb = (int)(B.size());
        if(szb > sza)
        {
            swap(sza, szb);
            swap(A, B);
            swap(c, d);
            cnt = j + Bloc - cnt;
        }
    }
    if(c == 'B')
        return cnt;
    else
        return n - cnt;
}
/*
int32_t main()
{
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    cin >> N;
    cin >> S;
    cout << count_mushrooms(N);
}
*/

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:104:9: warning: unused variable 'flag' [-Wunused-variable]
  104 |     int flag = 0;
      |         ^~~~

• Subtask 1: 92.623 / 100