bool dfs(char** board, int boardSize, int* boardColSize, char* word, int index, int row, int col) 
{
    //判断边界条件
    if (row < 0 || row == boardSize || col < 0 || col == *boardColSize || word[index] != board[row][col])
     {
    return false;
     }

    //index 记录board中word的字符个数
    if (index == strlen(word) - 1) return true;
    //记录本次的字符，将他置为空值，避免重复使用
    char temp = board[row][col];
    board[row][col] = '/';
    //递归找
    bool match = dfs(board, boardSize, boardColSize, word, index + 1, row + 0, col + 1) || 
                 dfs(board, boardSize, boardColSize, word, index + 1, row + 1, col + 0) || 
                 dfs(board, boardSize, boardColSize, word, index + 1, row + 0, col - 1) || 
                 dfs(board, boardSize, boardColSize, word, index + 1, row - 1, col + 0);

    board[row][col] = temp;
    return match;
}

bool exist(char** board, int boardSize, int* boardColSize, char* word){
    //枚举每一个board中的元素
    for (int i = 0; i < boardSize; ++i) {
        for (int j = 0; j < *boardColSize; ++j) {
            if (dfs(board, boardSize, boardColSize, word, 0, i, j))
             return true;
        }
    }
    return false;
}