quick_search

#include <iostream>

using namespace std;


// https://en.wikipedia.org/wiki/Rostov_Oblast


const char* text = R"(Residents identified
themselves as belonging to 157 different
ethnic groups, including 27 of more than 2,000
persons each. The largest ethnicities are[14]
the 3,795,607 Russians (90.3%);
the 110,727 Armenians (2.6%) and the 77,802
Ukrainians (1.9%). Other important groups
are the 35,902 Turks (0.9%); 16,493 Belarusians (0.4%);
13,948 Tatars (0.3%); 17,961 Azerbaijanis (0.4%); 11,449
Chechens (0.3%); 16,657 Romani (0.4%); 11,597 Koreans (0.3%);
8,296 Georgians (0.2%), and 2,040 Assyrians (.05%).
There were also 76,498 people (1.8%) belonging to
other ethno-cultural groupings. 76,735 people were
registered from administrative databases, and could
not declare an ethnicity. It is estimated that the proportion
of ethnicities in this group is the same as that of the declared
group.[21])";


void my_copy(char* des, int n, const char* src) {
    for (int k = 0; k < n; k++)
        des[k] = src[k];
}


int parse(const char* text, double*& out) {
    int num = 0;


    char* buff = new char[10];

    int len = strlen(text);
    cout << "len: " << len << endl;
    int bg = 0;
    int ed = 0;
    for (int k = 0; k < len; k++) {
        if (text[k] == '(')
            bg = k+1;
        if (text[k] == ')') {
            ed = k-1;
            my_copy(buff, ed-bg, &(text[bg]));
            buff[ed - bg] = '\0';
            out[num++] = atof(buff);
        }
    }
    delete[] buff;
    return num;
}


void task1() {
    char buff[10];
    auto out = new double[100];
    int num = parse(text, out);
    for (int k = 0; k < num; k++)
        cout << out[k] << ", ";
    cout << endl;
    delete[] out;
    /*
    for (int k = 0, n = 10; ((n > 0) && (k < 10)); k++, n--)
        cout << k << " " << n << endl;
    int data[5][5]{};
    for (int r = 0; r < 5; r++) {
        data[2][r] = 15 + r;
        data[4][r] = 15 - r;
    }
    for (int r = 0; r < 5; r++) {
        cout << data[2][r] - data[4][r];
    }
    */
}

int binary_search_recursion(int* arr, int left, int right, int target) {
    if (left <= right) {
        int midle = left + (right - left) / 2;
        if (arr[midle] == target) {
            return midle;
        }
        else if (arr[midle] > target) {
            binary_search_recursion(arr,left, midle-1, target);
        }
        else {
            binary_search_recursion(arr,midle+1, right, target);
        }
    } else
        return -1;
}

int binary_search(int* arr, int left, int right, int target) {
    while (left <= right) {
        int midle = left + (right - left) / 2;
        if (arr[midle] == target) {
            return midle;
        }
        else if (arr[midle] > target) {
            right = midle - 1;
        }
        else {
            left = midle + 1;
        }
    }
    return -1;
}

void test_binary_search() {
    int arr[]{1,2,3,4,5,6,7,8,9};
    cout << "7 at " << binary_search(arr,0,size(arr),7) << endl;
}

int main() {
    test_binary_search();
    return 0;
}