04.Snake

#include <iostream>
#include <list>
#include <string>

std::string repeatWord(std::string& word) {
    std::string repeated;
    for (int i = 0; i < 100; ++i) {
        repeated.append(word);
    }
    return repeated;
}

void makeSnake(std::list<std::list<char>>& snakeWords, std::string& word, int& rows, int& cols) {
    int wordIndex = 0;

    for (int i = 0; i < rows; ++i) {
        std::list<char> row;
        for (int j = 0; j < cols; ++j) {
            if (i % 2 == 0) {
                row.push_back(word[wordIndex]);
            }
            else {
                row.push_front(word[wordIndex]);
            }
            wordIndex++;
        }
        snakeWords.push_back(row);
    }
}

void printSnake(std::list<std::list<char>>& snakeWords) {
    for (auto& row : snakeWords) {
        for (auto& elem : row) {
            std::cout << elem;
        }
        std::cout << std::endl;
    }
}

int main() {
    int rows, cols;
    std::string word;
    std::cin >> rows >> cols >> word;

    std::list<std::list<char>> snakeWords;
    word = repeatWord(word);
    makeSnake(snakeWords, word, rows, cols);
    printSnake(snakeWords);
}