Cod sursa(job #3347142)

Utilizator Sabin1133Padurariu Sabin Sabin1133 Data 15 martie 2026 18:04:43
Problema Elementul majoritar Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.48 kb
#include <cstdlib>
#include <ctime>

#include <iostream>

#define NMAX 1000000

void quick_sort(int *v, int n)
{
    int a, pivot;
    int m = 0;

    if (n < 2)
        return;

    pivot = v[rand() % n];

    for (int i = 0, j = n - 1; 1; ++i, --j, ++m) {
        while (v[i] < pivot) {
            ++i;
            ++m;
        }

        while (v[j] > pivot)
            ++j;

        if (i >= j)
            break;

        a = v[i];
        v[i] = v[j];
        v[j] = a;
    }

    quick_sort(v, m);
    quick_sort(v + m, n - m);
}

int lower_bound(int *v, int n, int a)
{
    int l, r, m;

    l = 0;
    r = n - 1;

    while (l <= r) {
        m = l + ((r - l) >> 1);

        if (v[m] >= a)
            r = m - 1;
        else
            l = m + 1;
    }

    return l;
}

int upper_bound(int *v, int n, int a)
{
    int l, r, m;

    l = 0;
    r = n - 1;

    while (l <= r) {
        m = l + ((r - l) >> 1);

        if (v[m] <= a)
            l = m + 1;
        else
            r = m - 1;
    }

    return l;
}

int main()
{
    int n;
    int v[NMAX], a;
    int count;

    freopen("elmaj.in", "r", stdin);
    freopen("elmaj.out", "w", stdout);

    srand(time(nullptr));

    std::cin >> n;

    for (int i = 0; i < n; ++i)
        std::cin >> v[i];

    quick_sort(v, n);
    a = v[n / 2 /* + 1 - 1 */];
    count = upper_bound(v, n, a) - lower_bound(v, n, a);

    if (count < n / 2 + 1)
        std::cout << -1;
    else
        std::cout << a << ' ' << count << '\n';

    return 0;
}