Cod sursa(job #1849560)

Utilizator SmarandaMaria Pandele Smaranda Data 17 ianuarie 2017 17:57:47
Problema Statistici de ordine Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.95 kb
#include <cstdio>
#include <queue>

using namespace std;

const int N = 3000009;

int a [N];

int part(int st, int dr){
    int aux, m, p, i, j;

    m = (st + dr) / 2;
    p = a [m];
    i = st - 1;
    j = dr + 1;
    while (1){
        do {++i;}while(a [i] < p);
        do {--j;}while(a [j] > p);
        if (i < j) {
            aux = a [i];
            a [i] = a [j];
            a [j] = aux;
        }
        else return j;
    }
}

void quick(int st, int dr, int k){
    int m, sp;

    if (st < dr){
        sp = part(st, dr);
        if (sp - st + 1 >= k)
            quick(st, sp, k);
        else
            quick(sp + 1, dr, k - sp + st - 1);
    }
}

int main(){
    int n, i, k;

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

    scanf("%d%d", &n, &k);
    for (i = 1; i <= n; i++)
        scanf("%d", &a [i]);
    quick(1, n, k);
    printf("%d\n", a [k]);
    return 0;
}