K - Birthday Puzzle （ DFS遍历数组 ）
Today is the Birthday of a beautiful girl, she's happy and she's telling her friends loudly to bring her birthday gifts. One of her best friends who is fond of puzzles decided to bring her a very special gift, a magic box, this box cannot be opened unless the beautiful girl solves the mysterious puzzle written on the box and writes the answer on a small piece of paper under where the puzzle is written.Today
