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Submission #1073222

# Submission time Handle Problem Language Result Execution time Memory
1073222 2024-08-24T10:38:01 Z GrindMachine Rarest Insects (IOI22_insects) C++17
47.5 / 100
 150 ms 924 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
 
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
 
template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}
 
template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}
 
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
 
/*
 
refs:
https://youtu.be/mm5Nv81P5u8?t=19948
edi

first, figure out the #of distinct guys in the array

b.s on answer
let's say we want to check if ans < mid
go over all indices and put each value into the machine
if val > mid, then pop the recently added value from the machine
at the end, count the #of guys that were added to the machine
if cnt == mid*unique, then each guy appears at least mid #of times, so return false
otherwise, cnt < mid*unique, so there is at least 1 guy that appears < mid #of times, so return true
gets around 50 points

key idea for 100 points:
try to save operations between successive calls of b.s

cnt == mid*unique:
we increase the left bound of the b.s
there are only good guys in the machine
because we increase the left bound, these good guys will remain forever
no need to remove them and add them again (put them forever in the machine)

cnt < mid*unique:
we decrease the right bound of the b.s
if a guy is bad in this iteration, he would be bad in the successive iteration too
so ignore the bad guys
also, remember to remove the good guys in this iteration from the machine

if case 1 is true, mid*unique guys removed from consideration
if case 2 is true, at least active-mid*unique guys removed from consideration
mid*unique splits the active set into almost 2 equal halves
so at each stage, around n/2 guys are removed from consideration

so we get n+n/2+n/4+... = 2n queries
n queries for finding the #of unique guys
so around 3n queries in total
refer https://codeforces.com/blog/entry/105835?#comment-942719 for more details

further optimizations for full score:
set l and r bounds of the b.s optimally (l = 1, r = (n/unique)-1, ans = n/unique) (ans is at most n/unique)
stop adding guys to the machine once the limit (cnt == mid*unique) is reached
randomize the order in which the guys are added to the machine

*/
 
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
 
#include "insects.h"

int min_cardinality(int n) {
    int d = 0;

    {
        vector<int> v;
        rep(i,n){
            move_inside(i);
            if(press_button() > 1){
                move_outside(i);
            }       
            else{
                v.pb(i);
                d++;
            }  
        }

        trav(i,v){
            move_outside(i);
        }
    }

    int lo = 1, hi = n/d;
    int ans = -1;

    auto ok = [&](int mid){
        vector<int> v;
        rep(i,n){
            move_inside(i);
            if(press_button() > mid){
                move_outside(i);
            }
            else{
                v.pb(i);
            }
        }

        trav(i,v){
            move_outside(i);
        }

        return sz(v) == mid*d;
    };

    while(lo <= hi){
        int mid = (lo+hi) >> 1;
        if(ok(mid)){
            ans = mid;
            lo = mid+1;
        }
        else{
            hi = mid-1;
        }
    }

    return ans;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 10 ms 600 KB Output is correct
7 Correct 3 ms 344 KB Output is correct
8 Correct 7 ms 432 KB Output is correct
9 Correct 6 ms 344 KB Output is correct
10 Correct 11 ms 344 KB Output is correct
11 Correct 2 ms 344 KB Output is correct
12 Correct 6 ms 344 KB Output is correct
13 Correct 6 ms 344 KB Output is correct
14 Correct 8 ms 436 KB Output is correct
15 Correct 7 ms 344 KB Output is correct
16 Correct 5 ms 344 KB Output is correct
17 Correct 6 ms 600 KB Output is correct
18 Correct 3 ms 340 KB Output is correct
19 Correct 4 ms 344 KB Output is correct
20 Correct 5 ms 344 KB Output is correct
21 Correct 2 ms 600 KB Output is correct
22 Correct 2 ms 436 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 344 KB Output is correct
6 Correct 10 ms 600 KB Output is correct
7 Correct 3 ms 344 KB Output is correct
8 Correct 7 ms 432 KB Output is correct
9 Correct 6 ms 344 KB Output is correct
10 Correct 11 ms 344 KB Output is correct
11 Correct 2 ms 344 KB Output is correct
12 Correct 6 ms 344 KB Output is correct
13 Correct 6 ms 344 KB Output is correct
14 Correct 8 ms 436 KB Output is correct
15 Correct 7 ms 344 KB Output is correct
16 Correct 5 ms 344 KB Output is correct
17 Correct 6 ms 600 KB Output is correct
18 Correct 3 ms 340 KB Output is correct
19 Correct 4 ms 344 KB Output is correct
20 Correct 5 ms 344 KB Output is correct
21 Correct 2 ms 600 KB Output is correct
22 Correct 2 ms 436 KB Output is correct
23 Correct 73 ms 428 KB Output is correct
24 Correct 15 ms 344 KB Output is correct
25 Correct 40 ms 436 KB Output is correct
26 Correct 34 ms 672 KB Output is correct
27 Correct 60 ms 344 KB Output is correct
28 Correct 12 ms 344 KB Output is correct
29 Correct 61 ms 344 KB Output is correct
30 Correct 31 ms 344 KB Output is correct
31 Correct 45 ms 344 KB Output is correct
32 Correct 49 ms 688 KB Output is correct
33 Correct 41 ms 600 KB Output is correct
34 Correct 57 ms 412 KB Output is correct
35 Correct 47 ms 344 KB Output is correct
36 Correct 27 ms 600 KB Output is correct
37 Correct 38 ms 440 KB Output is correct
38 Correct 27 ms 592 KB Output is correct
39 Correct 20 ms 592 KB Output is correct
40 Correct 13 ms 340 KB Output is correct
41 Correct 10 ms 348 KB Output is correct

Subtask #3
22.5 / 75.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Partially correct 1 ms 344 KB Output is partially correct
7 Partially correct 150 ms 676 KB Output is partially correct
8 Correct 21 ms 448 KB Output is correct
9 Partially correct 80 ms 428 KB Output is partially correct
10 Partially correct 75 ms 600 KB Output is partially correct
11 Partially correct 118 ms 344 KB Output is partially correct
12 Correct 45 ms 420 KB Output is correct
13 Partially correct 130 ms 592 KB Output is partially correct
14 Partially correct 71 ms 344 KB Output is partially correct
15 Partially correct 113 ms 660 KB Output is partially correct
16 Partially correct 105 ms 676 KB Output is partially correct
17 Partially correct 123 ms 672 KB Output is partially correct
18 Partially correct 110 ms 676 KB Output is partially correct
19 Partially correct 115 ms 668 KB Output is partially correct
20 Partially correct 85 ms 592 KB Output is partially correct
21 Partially correct 68 ms 344 KB Output is partially correct
22 Partially correct 52 ms 592 KB Output is partially correct
23 Partially correct 37 ms 344 KB Output is partially correct
24 Correct 27 ms 344 KB Output is correct
25 Correct 29 ms 848 KB Output is correct
26 Correct 19 ms 344 KB Output is correct
27 Partially correct 93 ms 664 KB Output is partially correct
28 Partially correct 85 ms 436 KB Output is partially correct
29 Partially correct 119 ms 580 KB Output is partially correct
30 Partially correct 119 ms 664 KB Output is partially correct
31 Partially correct 54 ms 676 KB Output is partially correct
32 Partially correct 68 ms 672 KB Output is partially correct
33 Partially correct 62 ms 588 KB Output is partially correct
34 Partially correct 54 ms 600 KB Output is partially correct
35 Partially correct 74 ms 432 KB Output is partially correct
36 Partially correct 79 ms 672 KB Output is partially correct
37 Partially correct 61 ms 344 KB Output is partially correct
38 Partially correct 79 ms 344 KB Output is partially correct
39 Partially correct 76 ms 592 KB Output is partially correct
40 Partially correct 62 ms 340 KB Output is partially correct
41 Partially correct 97 ms 600 KB Output is partially correct
42 Partially correct 96 ms 900 KB Output is partially correct
43 Partially correct 14 ms 344 KB Output is partially correct
44 Partially correct 118 ms 600 KB Output is partially correct
45 Partially correct 146 ms 924 KB Output is partially correct
46 Correct 40 ms 588 KB Output is correct
47 Correct 51 ms 344 KB Output is correct
48 Correct 33 ms 344 KB Output is correct