Submission #961725

#	Time	Username	Problem	Language	Result	Execution time	Memory
961725		steveonalex	The Big Prize (IOI17_prize)	C++17	20 / 100	48 ms	3628 KiB

prize

#include <bits/stdc++.h>
#include "prize.h"

 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
 
// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
 
ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b){a = b; return true;}
        return false;
    }
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b){a = b; return true;}
        return false;
    }
template <class T>
    void printArr(T& a, string separator = " ", string finish = "\n"){
        for(auto i: a) cout << i << separator;
        cout << finish;
    }
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }
 
// namespace Interactor{
//     const int BLOCK = 400;
//     int n;
//     vector<int> a;

//     vector<int> ask(int i){
//         vector<int> ans(2);
//         for(int j = 0; j < i; ++j) ans[0] += (a[j] < a[i]);
//         for(int j = i+1; j<n; ++j) ans[1] += (a[j] < a[i]);
//         return ans;
//     }

    int range_query(set<int> &S, int l, int r){
        auto it = S.lower_bound(l);
        int cnt = 0;
        while(it != S.end()){
            if (*it > r) break;
            cnt++;
            it++;
        }
        return cnt;
    }

    void DnC(int l, int r, int ma, vector<pair<int, int>> &b, set<int> &S1, set<int> &S2){
        if (l > r) return;
        int x = (l + r) >> 1;
        if (b[x].first == -1){
            vector<int> cur= ask(x);
            b[x] = {cur[0], cur[1]};
        }
        if (b[x].first + b[x].second == ma){
            S1.insert(x);

            // look to the left
            auto it = S1.lower_bound(x); it--;
            int dL = b[x].first - b[*it].first;
            if (dL - range_query(S2, *it, x) > 0) DnC(l, x - 1, ma, b, S1, S2);

            // look to the right
            it = S1.upper_bound(x);
            if (it == S1.end()) {
                DnC(x + 1, r, ma, b, S1, S2);
                return;
            }
            dL = b[*it].first - b[x].first;
            if (dL - range_query(S2, x, *it) > 0) DnC(x + 1, r, ma, b, S1, S2);
        }
        else{
            S2.insert(x);
            DnC(l, x - 1, ma, b, S1, S2);
            DnC(x + 1, r, ma, b, S1, S2);
        }
    }

    int find_best(int n) {
        const int BLOCK = 450;
        vector<pair<int, int>> b(n, {-1, -1});
        if (n <= 1e4){
            for(int i = 0; i<n; ++i) {
                vector<int> cur = ask(i);
                if (cur[0] + cur[1] == 0) return i;
            }
        }
        int ma = 0;
        for(int i = 0; i<BLOCK; ++i){
            vector<int> cur = ask(i);
            b[i] = {cur[0], cur[1]};
            maximize(ma, cur[0] + cur[1]);
        }

        set<int> S1, S2;
        for(int i = 0; i<BLOCK; ++i){
            if (b[i].first + b[i].second == ma) S1.insert(i);
            else S2.insert(i);
        }

        DnC(BLOCK, n-1, ma, b, S1, S2);


        for(int i: S2) if (b[i].first + b[i].second == 0) return i;
        return -1;
    }

//     bool solve(){
//         n = 2e5;
//         a.resize(n, 3);
//         a[0] = 1;
//         for(int i = 1; i<=BLOCK; ++i) a[i] = 2;
//         // reverse(ALL(a));
//         shuffle(ALL(a), rng);

//         // printArr(a, "");

//         int j = find_best(n);
//         cout << "! " << j << "\n";
//         return a[j] == 1; 
//     }

// }

 
// int main(void){
//     ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

//     bool verdict = Interactor::solve();
//     if (verdict) cout << "AC\n";
//     else cout << "WA\n";

//     return 0;
// }

• Subtask 1: 20 / 20
• Subtask 2: 0 / 80