if_el_exist

#include <iostream>
#include <vector>
#include <string>
using namespace std;
string find_num(vector<vector<int>> mas, int num) {
    if (mas.size() == 1) {
        if (num == mas[0][0]) {
            return "yes";
        }
        else {
            return "no";
        }
    }
    int new_n = mas.size() / 2;
    int minus_1 = 0;
    if (mas.size() % 2 == 1) {
        minus_1 = -1;
    }
    while ((new_n + 1) != mas.size() && (new_n - 1) != 0) {
        if (mas[new_n + 1][new_n + 1] > num && mas[new_n][new_n] < num) {
            if (num == mas[new_n + 1][new_n] || num == mas[new_n][new_n + 1]) {
                return "yes";
            }
            else {
                return "no";
            }
        }
        else if (mas[new_n - 1][new_n - 1] < num && mas[new_n][new_n] > num) {
            if (num == mas[new_n - 1][new_n] || num == mas[new_n][new_n - 1]) {
                return "yes";
            }
            else {
                return "no";
            }
        }
        else {
            new_n = new_n + (mas.size() - new_n) / 2;
        }
    }
    int s = mas.size() - 1;
    if (mas[0][0] == num || mas[0][1] == num || mas[1][1] == num || mas[1][0] == num
        || mas[s][s] == num || mas[s][s - 1] == num || mas[s - 1][s] == num || mas[s - 1][s - 1] == num) {
        return "yes";
    }
    else {
        return "no";
    }
}
int main() {
    int n;
    cin >> n;
    vector<vector<int>> mas(n, vector<int>(n));
    for (auto& v : mas) {
        for (auto& el : v) {
            int element;
            cin >> element;
            el = element;
        }
    }
    int number;
    cin >> number;
    cout << find_num(mas, number) << endl;
    system("pause");
    return 0;
}