Submission #470656

#	Time	Username	Problem	Language	Result	Execution time	Memory
470656		Carmel_Ab1	The Big Prize (IOI17_prize)	C++17	20 / 100	105 ms	2452 KiB

prize

#include "prize.h"
#include <bits/stdc++.h>
using namespace std;
typedef vector<int>vi;
typedef pair<int,int>pi;
typedef vector<pi> vpi;
#define pb push_back
#define all(x) x.begin(),x.end()
//#include "grader.cpp"
struct seg{
    int sz=1;
    vi t;
    seg(int n){
        while(sz<=2*n)
            sz*=2;
        t.resize(sz);
    }
    int query(int i){
        i+=sz/2;
        while(i){
            if(t[i])
                return 1;
            i/=2;
        }
        return 0;
    }
    void update(int l,int r){
        for(l+=sz/2,r+=sz/2 +1; l<r; l/=2,r/=2){
            if(l&1)t[l++]++;
            if (r&1)t[--r]++;
        }
    }
};
int find_best(int n) {

    int sz=50;
    vi prv={-1,-1};
    vpi segs;
    for(int i=0; i<n; i+=sz){
        vi s=(prv[0]==-1?ask(i):prv),e=ask(min(n-1,i+sz));
        if(s[0]==0 && s[1]==0)
            return i;
        if(e[0]==0 && e[1]==0)
            return min(i+sz,n-1);
        if(e[0]==s[0])
            continue;
        segs.pb({i,min(i+sz,n-1)});
        prv=e;
    }

    srand(time(0));
    random_shuffle(all(segs));
    seg s(2e5);

    for(pi p:segs){
        int l=p.first,r=p.second;
        for(int i=l+1; i<r; i++){
            if(s.query(i))
                continue;
            vi v=ask(i);
            if(v==vi(2,0))
                return i;
            if(v[0]==0)
                s.update(0,i);
            if(v[1]==0)
                s.update(i,n-1);
        }
    }
    assert(0);
    return -1;
}

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