Submission #577452

#	Time	Username	Problem	Language	Result	Execution time	Memory
577452		Theo830	The Big Prize (IOI17_prize)	C++17	95.77 / 100	54 ms	400 KiB

prize

#include <bits/stdc++.h>
using namespace std;
typedef int ll;
const ll INF = 1e9+7;
const ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<ll,ii>
#define ull unsigned int
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
//int find_best(int n);
//std::vector<int> ask(int i);
#include "prize.h"
ll maxi = 0;
ll solve(ll l,ll r,ll L,ll R){
    if(l > r){
        return -1;
    }
    ll mid = (l+r)/2;
    vector<int>res = ask(mid);
    if(res[0] == 0 && res[1] == 0){
        return mid;
    }
    if(l == r){
        return -1;
    }
    ll ans = -1;
    ll left = mid,right = mid;
    ll cur = 0;
    while(res[0] + res[1] < maxi){
        if(cur == 0){
            left--;
            if(left >= l){
                res = ask(left);
                if(res[0] == 0 && res[1] == 0){
                    return left;
                }
            }
        }
        else{
            right++;
            if(right <= r){
                res = ask(right);
                if(res[0] == 0 && res[1] == 0){
                    return right;
                }
            }
        }
        if(left < l && right > r){
            break;
        }
        cur ^= 1;
    }
    if((res[0] + res[1]) == maxi){
        if(res[0] != L){
            ans = solve(l,left - 1,L,res[1]);
        }
        if(res[1] != R && ans == -1){
            ans = solve(right + 1,r,res[0],R);
        }
    }
    return ans;
}
int find_best(int n){
    srand(time(0));
    ll k = 500;
    while(k--){
        vector<int> res = ask(rand() % n);
        maxi = max(maxi,res[0] + res[1]);
    }
    return solve(0,n-1,0,0);
}
/*
static const int max_q = 10000;
static int n;
static int query_count = 0;
vector<int> g;
static vector<vector<int> > rank_count;

vector<int> ask(int i) {
    //cout<<i<<endl;
    query_count++;
    if(query_count > max_q) {
        cerr << "Query limit exceeded" << endl;
        exit(0);
    }

    if(i < 0 || i >= n) {
        cerr << "Bad index: " << i << endl;
        exit(0);
    }

    vector<int> res(2);
    res[0] = rank_count[g[i] - 1][i + 1];
    res[1] = rank_count[g[i] - 1][n] - res[0];
    return res;
}

int main() {
    n = 1 + 2 + 5 + 30 + 200000;
    g.pb(1);
    g.pb(2);
    g.pb(2);
    f(k,0,5){
        g.pb(3);
    }
    f(k,0,30){
        g.pb(4);
    }
    f(k,0,200000){
        g.pb(5);
    }
    random_shuffle(all(g));
    int max_rank = *max_element(g.begin(), g.end());

    rank_count.resize(max_rank + 1, vector<int>(n + 1, 0));
    for(int r = 0; r <= max_rank; r++) {
        for(int i = 1; i <= n; i++) {
            rank_count[r][i] = rank_count[r][i - 1];
            if(g[i - 1] == r)
              rank_count[r][i]++;
        }
    }

    for(int i = 0; i <= n; i++)
        for(int r = 1; r <= max_rank; r++)
            rank_count[r][i] += rank_count[r - 1][i];
    int res = find_best(n);
    assert(g[res] == 1);
    cout << res << endl << "Query count: " << query_count << endl;

    return 0;
}
*/

• Subtask 1: 20 / 20
• Subtask 2: 75.77 / 80