Cod sursa(job #2542445)

Utilizator DanutAldeaDanut Aldea DanutAldea Data 9 februarie 2020 23:30:43
Problema Statistici de ordine Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.85 kb
#include <fstream>
#include <random>
#include <time.h>
using namespace std;

ifstream fin("sdo.in");
ofstream fout("sdo.out");

int n,k,i,j,v[500001];

int poz(int st, int dr){
    int x=st+rand()%(dr-st+1);
    swap(v[x],v[st]);

    int dst=0;
    int ddr=-1;
    int aux;

    while(st<dr){
        if(v[st]>v[dr]){
            swap(v[st],v[dr]);
            aux=ddr;
            ddr=-dst;
            dst=-aux;
        }

        st+=dst;
        dr+=ddr;
    }

    return st;
}

int solve(int st, int dr){
    if(st==dr)
        return v[st];

    int p=poz(st,dr);

    if(p==k)
        return v[k];

    if(p<k)
        solve(p+1,dr);
    else
        solve(st,p-1);
}

int main(){
    srand(time(0));

    fin>>n>>k;
    for(i=1;i<=n;i++){
        fin>>v[i];
    }

    fout<<solve(1,n);

    return 0;
}