Common Programming Operations

Alphabetical Sorting of String

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Java

char[] charArray = s.toCharArray();
Arrays.sort(charArray);
String sorted = new String(charArray);

• To sort a string, we first need to convert it into a character array
• The Arrays.sort() method is a void method and does not return a value. it sorts the array in place.
• Finally, we need to convert the sorted character array back into a string

Python

sorted_arr = ''.join(sorted(s))

• We can sort a string using sorted() without converting it to a character array.
• However, we still need to use ''.join() to obtain a sorted string because sorted() returns a list

C++

string sorted = s;
sort(sorted.begin(), sorted.end());

• C++ std::sort() works directly on a std::string without needing to convert it to a character array, because a std::string in C++ is essentially a sequence of characters (similar to a char array)
• Just like in Java, std::sort() returns void

Defining Custom Comparison Logic

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Java

class Node implements Comparable<Node> {
    public int freq;
   
    @Override
    public int compareTo(Node other) {
        return Integer.compare(other.freq, this.freq);
    }
}

• The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and this.freq
• For more details, refer to Java Comparison

Python

class Node:
    def __init__(self, val, freq):
        self.freq = freq
    
    def __lt__(self, other):
        return other.freq < self.freq 

• The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and self.freq

C++

class Node {
public:
    int freq;
 
	Node(int freq) {
		this->freq = freq;
	}
 
	bool operator<(const Node& other) {
		return other.freq > this->freq;
	}
}

• The comparator logic above implements a descending order. To achieve ascending order, swap other.freq and self->freq

Heap Manipulation

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Java

// Create a min-heap
PriorityQueue<Integer> minHeap = new PriorityQueue<>();
 
// Add a new element to the heap
minHeap.add(5);
 
// Remove and return the smallest element from the heap
minHeap.poll();

Python

# # Create a list to serve as a container for the min-heap
minHeap = []
# Convert the list with elements into a min-heap
heapq.heapify(minHeap)
 
# Add a new element to the heap
heapq.heappush(minHeap, 5)
 
# Remove and return the smallest element from the heap
heapq.heappop(minHeap)

C++

// Create a min-heap
priority_queue<int> minHeap;
 
// Add Add a new element to the heap
minHeap.push(5);
 
// Remove the smallest element from the heap
minHeap.pop();
// Return the smallest element from the heap
minHeap.top().val;

Convert HTML to TXT

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Important

We don’t want to extract the content as a single string because this would result in losing all the formatting information provided by the HTML tags. Reformatting the content based on the document structure afterward is tedious, error-prone, and not scalable.

Instead, the idea is to retain the formatting information we need before removing all the HTML tags. Then, we can use this retained formatting information to generate a text file with the desired formatting.

Java

// Generate a placeholder string using UUID to avoid conflicts with the HTML content
String uniquePlaceholder = UUID.randomUUID().toString();
 
// This step retains line break information, which we will later replace with actual line breaks (\n)
String htmlContent = rawHtml.replace("<br />", "<span>" + uniquePlaceholder + "</span>");
 
// Parse the modified HTML content using Jsoup to extract plain text
// Replace the placeholder with actual line breaks (\n) to simulate the original formatting
String txtContent = Jsoup.parse(htmlContent).text().replace(uniquePlaceholder, "\n");
 
// Create a FileWriter to write the plain text content to a file
FileWriter writer = new FileWriter("output.txt");
 
// Write the plain text content into the file
writer.write(txtContent);
 
writer.close();
 

Code

This above code example assumes that <br /> is the only tag used to denote line breaks in the given HTML string. If other tags or methods are used for formatting, additional handling may be required.

Also note that, The FileWriter writer formats and writes the content into a text file, ensuring that line breaks are correctly represented using \n.