Submission #594970

#	Time	Username	Problem	Language	Result	Execution time	Memory
594970		MadokaMagicaFan	Counting Mushrooms (IOI20_mushrooms)	C++14	80.71 / 100	11 ms	732 KiB

mushrooms

#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;

#define all(v)          v.begin(),v.end()
#define sort(v)         sort(all(v))
#define endl            '\n'
#define forn(i,n)       for(int i = 0; i < n; ++i)
#define forbe(i,b,e)    for(int i = b; i < e; ++i)
#define forr(i,n)       for(int i = n-1; i >= 0; --i)
#define sz(v)           ((int)v.size())
#define pb              push_back
#define f               first
#define s               second

int use_machine(vi x);

int count_mushrooms(int n) {
    vi type(n, 1);
    vi s(n,1);
    type[0] = 1;

    int ans = 1;

    vi a;
    vi b;

    a.pb(0);

    int pnt = 1;

    vi ask;
    int val;
    while (pnt < n) {
        ask.clear();
        if (sz(a) > sz(b)) {
            for (pnt; pnt < n && sz(ask) < (sz(a)<<1); ++pnt) {
                ask.pb(a[sz(ask)>>1]);
                ask.pb(pnt);
            }

            ans += (sz(ask)>>1);
            val = use_machine(ask);

            ans -= ((val+1)>>1);

            if (val == 0) {
                for (int i = 1; i < sz(ask); i+=2)
                    a.pb(ask[i]);
            } else if (val + 1 == sz(ask)) {
                for (int i = 1; i < sz(ask); i+=2)
                    b.pb(ask[i]);
            } else if (val&1) 
                b.pb(pnt-1);
            else
                a.pb(pnt-1);
        } else {
            for (pnt; pnt < n && sz(ask) < (sz(b)<<1); ++pnt) {
                ask.pb(b[sz(ask)>>1]);
                ask.pb(pnt);
            }

            val = use_machine(ask);

            ans += ((val+1)>>1);

            if (val == 0) {
                for (int i = 1; i < sz(ask); i+=2)
                    b.pb(ask[i]);
            } else if (val + 1 == sz(ask)) {
                for (int i = 1; i < sz(ask); i+=2)
                    a.pb(ask[i]);
            } else if (val&1) 
                a.pb(pnt-1);
            else
                b.pb(pnt-1);
        }
    }

//    while (s[0] < n) {
//        for (int i = 0; i < n;) {
//            assert(i+s[i] <= n);
//            if (i + s[i] == n)
//                break;
//            
//            if (use_machine({i, i + s[i]})) {
//                forbe(j, i+s[i], i+s[i]+s[i+s[i]])
//                    type[j] = 1 - type[j];
//            }
//
//            s[i] += s[i+s[i]];
//
//            i += s[i];
//        }
//    }

//    forn(i, n)
//        ans += type[i];
//    forn(i, n)
//        cout << type[i] << ' ';
//        cout << endl;

//    for(int i = 2; i < n; i+=2) {
//        ans += 2 - use_machine({i, 0, i-1});
//    }
//
//    if ((n&1)==0)
//        ans += 1 - use_machine({n-1,0});

    return ans;
}

#ifdef ONPC
vi rans;

int cnt = 0;

int use_machine(vi x){
    ++ cnt;
    int _ans = 0;
//    cout << "ASK: ";
//    forn(i , sz(x))
//        cout << x[i] << ' ';
//        cout << endl;
    forn(i , sz(x)-1)
        if (rans[x[i]] != rans[x[i+1]])
            ++_ans;
//    cout << "ANSWER: " << _ans << endl;
    return _ans;
}

void solve() {
    int n;
    cin >> n;

    rans.resize(n);

    char c;

    int ranswer = 0;

    forn(i, n) {
        cin >> c;
        rans[i]=(c=='A');

        if (c=='A') ++ranswer;
    }

    int cans = count_mushrooms(n);

    if (cans != ranswer)
        forn(i, n)
            cout << rans[i] << ' ';

    cout << endl;
    cout << cans << ' ' << ranswer << endl;
    cout << n << ' ' << cnt << endl;
}

int main() {
//    freopen("in", "r", stdin);
//    ios_base::sync_with_stdio(0);cin.tie(0);
    solve();
}
#endif

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:41:18: warning: statement has no effect [-Wunused-value]
   41 |             for (pnt; pnt < n && sz(ask) < (sz(a)<<1); ++pnt) {
      |                  ^~~
mushrooms.cpp:62:18: warning: statement has no effect [-Wunused-value]
   62 |             for (pnt; pnt < n && sz(ask) < (sz(b)<<1); ++pnt) {
      |                  ^~~

• Subtask 1: 80.7143 / 100