Cod sursa(job #1890486)

Utilizator calin13Calin Nicolau calin13 Data 23 februarie 2017 12:12:23
Problema Cautare binara Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.8 kb
#include <fstream>
#include <vector>
#include <iostream>
using namespace std;

int cautbin(const vector<int> &v, int x)
{
    int i = 0, j = v.size();
    while (i < j) {
        int m = i + (j-i)/2;
        if (x < v[m]) {
            j = m-1;
        } else if (x > v[m]){
            i = m+1;
        } else {
            return m;
        }
    }
    return -1;
}

int upper(const vector<int> &v, int x)
{
    int i = 0, j = v.size()-1;
    while (i < j) {
        int m = i + (j-i)/2;
        if (x > v[m]) {
            i = m+1;
        } else {
            j = m;
        }
    }
    return i;
}

int lower(const vector<int> &v, int x)
{
    int i = 0, j = v.size();
    while (i < j) {
        int m = i + (j-i)/2;
        if (x < v[m]) {
            j = m-1;
        } else {
            i = m;
        }
    }
    return i;
}

int main()
{
    ios_base::sync_with_stdio(false);
    ifstream f("cautbin.in");
    int n;
    f >> n;
    vector<int> v(n);
    for (int i = 0; i < n; ++i) {
        f >> v[i];
    }
    int m;
    f >> m;
    ofstream g("cautbin.out");
    for (int i = 0; i < m; ++i) {
        int op, x;
        f >> op >> x;

        if (op == 0) {
            int pos = cautbin(v, x);
            if (pos > 0) {
                while (v[pos] == x) ++pos;
            }
            g << pos << '\n';
        } if (op == 1) {
            int pos = lower(v, x);
            while (pos < v.size()-1 && v[pos+1] == x) {
                ++pos;
            }
            g << pos + 1 << '\n';
        } if (op == 2) {
            int pos = upper(v, x);
            while (pos > 0 && v[pos-1] == x) {
                --pos;
            }
            g << pos + 1 << '\n';
        }
    }
    f.close();
    g.close();
    return 0;
}