Submission #699407

#	Time	Username	Problem	Language	Result	Execution time	Memory
699407		MasterTaster	The Big Prize (IOI17_prize)	C++14	20 / 100	94 ms	448 KiB

prize

#include "prize.h"
#include <iostream>
#include <vector>
#include <cmath>

#define ll long long
#define pii pair<int, int>
#define xx first
#define yy second
#define pb push_back
#define MAXN 200010

using namespace std;

int n, l[MAXN], r[MAXN], maxx, sq=490;
vector<int> all;

/*bool check(int i, int k)
{
    vector<int> p=ask(i);
    int le=p[0], ri=p[1];
    if ((le+ri)<maxx) return true;
    if (le>k) return true;
    return false;
}*/

bool vis[MAXN];
void askk(int i)
{
    if (!vis[i]) { vector<int> p=ask(i); l[i]=p[0]; r[i]=p[1]; vis[i]=true; }
}

void solve(int left, int right)
{
    int mid=left+(right-left)/2;
    askk(mid);

    if (left>right) return;
    if (left==right) { if ((l[mid]+r[mid])<maxx) all.pb(mid); return; }
    if (left==(right-1))
    {
        if ((l[mid]+r[mid])<maxx) all.pb(mid);
        mid++;
        askk(mid);
        if ((l[mid]+r[mid])<maxx) all.pb(mid);
        return;
    }

    if ((l[mid]+r[mid])<maxx) { all.pb(mid); solve(left, mid-1); solve(mid+1, right); }
    else
    {
        if (l[mid]) solve(left, mid-1);
        if (r[mid]) solve(mid+1, right);
    }
}

int find_best(int N) {
    n=N;
    sq=min(sq, n-1);//2*sqrt(n);
    for (int i=0; i<=sq; i++)
    {
        askk(i);
        maxx=max(maxx, l[i]+r[i]);
    }

    int left=0, right=n-1;
    solve(left, right);

    /*int lf=0; int rr=n-1;
    for (int i=0; i<maxx; i++)
    {
        int where=-1;
        while (lf<=rr)
        {
            int mid=lf+(rr-lf)/2;
            if (check(mid, all.size()))
            {
                where=mid;
                rr=mid-1;
            }
            else
                lf=mid+1;
        }
        //cout<<where<<endl;
        all.pb(where);
        lf=where+1;
        rr=n-1;
    }*/

    int ret=0;
    for (int i=0; i<all.size(); i++) { /*askk(all[i]);*/ if ((l[all[i]]+r[all[i]])==0) ret=all[i]; }
    return ret;
}
///1, 2, 5, 26, 677
/*
8
3 2 3 1 3 3 2 3
*/

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:91:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |     for (int i=0; i<all.size(); i++) { /*askk(all[i]);*/ if ((l[all[i]]+r[all[i]])==0) ret=all[i]; }
      |                   ~^~~~~~~~~~~

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