Submission #628924

#	Time	Username	Problem	Language	Result	Execution time	Memory
628924		dqhungdl	Rarest Insects (IOI22_insects)	C++17	57.13 / 100	162 ms	328 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
using namespace std;

int diff = 0;
vector<bool> mark;

void countDiff(int N) {
    for (int i = 0; i < N; i++) {
        move_inside(i);
        if (press_button() == 1) {
            diff++;
            mark[i] = true;
        } else
            move_outside(i);
    }
}

bool check(int lim, int N) {
    if (press_button() > lim) {
        for (int i = 0; i < N; i++)
            if (mark[i]) {
                mark[i] = false;
                move_outside(i);
            }
    }
    int cnt = accumulate(mark.begin(), mark.end(), 0);
    for (int i = 0; i < N; i++)
        if (!mark[i]) {
            move_inside(i);
            if (press_button() > lim)
                move_outside(i);
            else {
                cnt++;
                mark[i] = true;
            }
        }
    return cnt < lim * diff;
}

int min_cardinality(int N) {
    mark.resize(N);
    countDiff(N);
    if (diff == N)
        return 1;
    int LIM = N / diff, step = max(LIM / 5, 1);
    int l, r, rs = 1;
    for (int i = step + 1; i <= LIM; i += step) {
        if (check(i, N)) {
            l = i - step + 1, r = i - 1;
            break;
        }
        rs = i;
        if (i + step > LIM)
            l = i + 1, r = LIM;
    }
    while (l <= r) {
        int mid = (l + r) / 2;
        if (check(mid, N))
            r = mid - 1;
        else {
            rs = mid;
            l = mid + 1;
        }
    }
    return rs;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:58:22: warning: 'r' may be used uninitialized in this function [-Wmaybe-uninitialized]
   58 |         int mid = (l + r) / 2;
      |                   ~~~^~~~
insects.cpp:58:22: warning: 'l' may be used uninitialized in this function [-Wmaybe-uninitialized]

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 32.13 / 75