Cod sursa(job #2061598)

Utilizator moise_alexandruMoise Alexandru moise_alexandru Data 9 noiembrie 2017 15:36:59
Problema Cautare binara Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 2.25 kb
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int maxn = 100005;
const int max_size = 100005;
char txt[max_size];
int v[maxn];
char T[25];
int logn;
int n;
inline int cautbin_0(int x)
{
    int i, pas;
    for (pas = 1; pas < n; pas <<= 1);
    for (i = 0; pas; pas >>= 1)
        if (i + pas <= n && v[i + pas] <= x)
           i += pas;
    return i;
}

inline int cautbin_2(int x)
{
    int st = 1;
    int dr = n;
    int ret = -1;
    while(st <= dr)
    {
        int mij = st + (dr - st + 1) / 3;
        if(x <= v[mij])
        {
            ret = mij;
            dr = mij - 1;
        }
        else
        {
            int mij2 = st + (dr - st + 1) / 3 * 2;
            if(mij2 < st || mij2 > dr)
                st = mij + 1;
            else
            {
                if(x <= v[mij2])
                {
                    ret = mij2;
                    dr = mij2 - 1;
                }
                else
                {
                    dr = mij2 - 1;
                    st = mij + 1;
                }
            }
        }
    }
    return ret;
}

int poz = max_size - 1;
FILE *fin;
FILE *fout;
inline void parsare(int &nr)
{
    nr = 0;
    while(!isdigit(txt[poz]))
    {
        if(++poz == max_size)
        {
            fread(txt, 1, max_size, fin);
            poz = 0;
        }
    }
    while(isdigit(txt[poz]))
    {
        nr = nr * 10 + txt[poz] - '0';
        if (++poz == max_size)
        {
            fread(txt, 1, max_size, fin);
            poz = 0;
        }
    }
}

int main()
{
    fin = fopen("cautbin.in", "r");
    fout = fopen("cautbin.out", "w");
    parsare(n);
    for(int i = 1; i <= n; i++)
        parsare(v[i]);
    int m;
    parsare(m);
    for(int i = 1; i <= m; i++)
    {
        int x = 0;
        int y = 0;
        parsare(x);
        parsare(y);
        if(x == 0 || x == 1)
        {
            int sol = cautbin_0(y);
            if(x == 0 && v[sol] != y)
                fprintf(fout, "-1");
            else
                fprintf(fout, "%d", sol);
        }
        else
            fprintf(fout, "%d", cautbin_2(y));
        fprintf(fout, "\n");
    }
    return 0;
}