C++ Chanel

#include <iostream>
#include <set>
#include <map>
#include <vector>
using namespace std;
 
 
int main() {
    int t{};
    cin>>t;
    vector<string> res;
    for(int g = 0;g<t;++g){
        int n;
        cin>>n;
        string result;
        vector<int> v(n,0);
        for(int i = 0;i<n;++i){
            cin>>v[i];
        }
        map<char,int> m; 
 
        for(int i = 0;i<n;++i){
            int w = 97;
            for(int j = 0;j<26;++j){
                if(m[w] == v[i]){
                    result+=(char)(w);
                    ++m[w];
                    break;
                }else{
                    w++;
                }
            }   
        }
        res.push_back(result);
    }
    for(string s : res){
        cout<<s<<endl;
    }
    
    return 0;
}

#include <iostream>
#include <set>
using namespace std;
int main()
{
    int n;
    cin >> n;
    int p;
    int q;
    set<int> res;
    cin >> p;
    for (int i = 0; i < p; ++i) {
        int temp;
        cin >> temp;
        res.insert(temp);
    }
    cin >> q;
    for (int i = 0; i < q; ++i) {
        int temp;
        cin >> temp;
        res.insert(temp);
    }
    if (res.size() == n && *--res.end() == n) {
        cout << "I become the guy.";
    }
    else {
        cout << "Oh, my keyboard!";
    }

    return 0;
}

*—a.end()

class Solution {
public:
    int maxLengthBetweenEqualCharacters(string s) {

        int result {-1};

        for(int i = 0;i<s.size();++i){

            for(int j = i+1;j<s.size();++j){

                if(s[i] == s[j])
                    result = max(j-i-1,result);

            }
        }
        
        return result;
    }
};

#include <iostream>

class Artist {
public:
    void Start() {
        Requesting();
    }
private:

    void Requesting() {
        std::string figure;
        bool run = 0; // run будет равна false
        std::cout << "Write what figure you want to draw: \n 1: Romb \n 2: Square \n 3: Triangle \n Write number or figure name: ";
        std::cin >> figure;
        while (!run) {
            if (figure == "1" || figure == "Romb") {
                DrawRomb();
                break;
            }
            else if (figure == "2" || figure == "Square") {
                DrawSquare();
                break;
            }
            else if (figure == "3" || figure == "Triangle") {
                DrawTriangle();
                break;
            }
            else {
                std::cout << "Please enter again: ";
                std::cin >> figure;
            }
        }
    }
    void DrawRomb() {
        int radius{}; // radius == 0
        std::cout << "Enter radius: ";
        std::cin >> radius;
        std::cout << "\n";
        int xval = radius;
        bool part1 = 1;
        int sval = radius + 1;
        for (int i = 0; i < (radius * 2) + 1; ++i) {
            for (int j = 0; j < (radius * 2) + 2; ++j) {
                if (j == xval || j == sval) {
                    if (j == xval) {
                        std::cout << "x";
                    }
                    if (j == sval) {
                        std::cout << "s";
                    }
                }
                else {
                    std::cout << " ";
                }
            }
            if (i >= radius)part1 = false;
            if (part1) {
                --xval;
                ++sval;
            }
            else {
                ++xval;
                --sval;
            }
            std::cout << std::endl;
        }

    }

    void DrawTriangle() {
        int height{};
        char c;
        std::cout << "Write height: ";
        std::cin >> height;
        std::cout << "\nWrite symbol to draw triangle: ";
        std::cin >> c;
        int index = height;
        int index2 = height - 1;
        std::cout << "\n";
        for (int y = 0; y < height; ++y) {
            for (int x = 0; x < height * 2; ++x) {
                if (y == height - 1)
                    std::cout << c;
                else if (x == index || x == index2)
                    std::cout << c;
                else std::cout << ' ';

            }
            index++;
            index2--;
            std::cout << "\n";
        }
    }

    void DrawSquare() {
        int size{};
        std::string temp;
        std::cout << "Write size of side: ";
        std::cin >> size;
        std::cout << "\nFilled? (yes/no): ";
        std::cin >> temp;
        bool filled = temp == "yes";

        if (!filled) {
            for (int y = 0; y < size; ++y) {
                for (int x = 0; x < size; ++x) {
                    if (y == 0 || y == size - 1)
                        std::cout << '#';
                    else if (x == 0 || x == size - 1)
                        std::cout << '#';
                    else
                        std::cout << ' ';
                }
                std::cout << "\n";

            }
        }
        else {
            for (int y = 0; y < size; ++y) {
                for (int x = 0; x < size; ++x) {
                    std::cout << '#';
                }
                std::cout << "\n";

            }
        }
    }
};


int main() {
    Artist art;
    art.Start();

    return 0;
}

  tree->val != NULL  

class Solution {
int result{};
public:
    int rangeSumBST(TreeNode* root, int low, int high) {
        if(root == NULL)return result;
        
        if(root->val >= low && root->val <= high)result += root->val;

        rangeSumBST(root->left,low,high);
        rangeSumBST(root->right,low,high);

        return result;
    }
};

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
int result = 0;
public:
    int rangeSumBST(TreeNode* root, int low, int high) {
        if(root == NULL)return result;
        
        if(root->val >= low && root->val <= high)result += root->val;

        rangeSumBST(root->left,low,high);
        rangeSumBST(root->right,low,high);

        return result;
    }
};