dsa/Sorting/VisualMergeSort.java

import java.util.ArrayList;

public class VisualMergeSort {
    static String RESET = "\u001B[0m";
    static String RED = "\u001B[31m";
    static String GREEN = "\u001B[32m";
    static String YELLOW = "\u001B[33m";
    static String BLUE = "\u001B[34m";
    static String PURPLE = "\u001B[35m";
    static String CYAN = "\u001B[36m";
    static String WHITE = "\u001B[37m";
    static String BOLD = "\u001B[1m";
    static String UNDERLINE = "\u001B[4m";
    static String ITALIC = "\u001B[3m";

    static int level = 0;

    public static void main(String[] args) {
        int[] array = {38, 27, 43, 3, 9, 82, 10};
        System.out.println("Original array:");
        printArray(array);

        // Initialize level and call mergeSort
        mergeSort(array, 0, array.length - 1, level);

        System.out.println("Sorted array:");
        printArray(array);
    }

    // Method to perform merge sort with level parameter
    public static void mergeSort(int[] array, int left, int right, int currentLevel) {
        if (left < right) {
            int mid = (left + right) / 2;
            System.out.printf("Dividing array from index %d to %d and mid %d\n", left, right, mid);
            System.out.printf("Current subarray: ");
            printArray(array, left, right);
            System.out.println();

            // Recursively sort the first and second halves
            int newLevel = currentLevel + 1;
            System.out.printf("%sCalling the first mergeSort with left = %d and right = %d with level %d%s\n", YELLOW, left, mid, newLevel, RESET);
            System.out.printf("First subarray: ");
            printArray(array, left, mid);
            System.out.println();
            mergeSort(array, left, mid, newLevel);

            System.out.printf("%sCalling the second mergeSort with left = %d and right = %d with level %d%s\n", BLUE, mid + 1, right, newLevel, RESET);
            System.out.printf("Second subarray: ");
            printArray(array, mid + 1, right);
            System.out.println();
            mergeSort(array, mid + 1, right, newLevel);

            // Merge the sorted halves
            merge(array, left, mid, right, newLevel);
        } else {
            System.out.printf("%sBase condition reached with left = %d and right = %d %s\n", GREEN, left, right, RESET);
        }
    }

    public static void merge(int[] arr, int low, int mid, int high, int currentLevel) {
        ArrayList<Integer> temp = new ArrayList<>(); // temporary array
        int left = low;      // starting index of left half of arr
        int right = mid + 1;   // starting index of right half of arr
        
        System.out.printf("%sMerging subarrays from index %d to %d and %d to %d with level %d%s\n", UNDERLINE, left, mid, mid + 1, right, currentLevel, RESET);
        System.out.printf("Subarrays before merge: ");
        printArray(arr, left, mid);
        System.out.printf("and ");
        printArray(arr, mid + 1, right);
        System.out.println();
    
        // Storing elements in the temporary array in a sorted manner
        while (left <= mid && right <= high) {
            if (arr[left] <= arr[right]) {
                temp.add(arr[left]);
                left++;
            } else {
                temp.add(arr[right]);
                right++;
            }
            System.out.printf("Placing %d at index %d\n", temp.get(temp.size() - 1), temp.size() - 1);
        }
    
        // If elements on the left half are still left
        while (left <= mid) {
            temp.add(arr[left]);
            System.out.printf("Placing %d at index %d\n", temp.get(temp.size() - 1), temp.size() - 1);
            left++;
        }
    
        // If elements on the right half are still left
        while (right <= high) {
            temp.add(arr[right]);
            System.out.printf("Placing %d at index %d\n", temp.get(temp.size() - 1), temp.size() - 1);
            right++;
        }
    
        // Transferring all elements from temporary to arr
        for (int i = low; i <= high; i++) {
            arr[i] = temp.get(i - low);
        }
        
        System.out.printf("Merged array from index %d to %d: ", low, high); // Correct indices
        printArray(arr, low, high); // Correct indices
        System.out.println();
    }
    

    // Utility method to print the array
    public static void printArray(int[] array) {
        System.out.printf("%s", BOLD);
        System.out.printf("%s", PURPLE);
        System.out.printf("%s", ITALIC);
        for (int value : array) {
            System.out.print(value + " ");
        }
        System.out.printf("%s", RESET);
        System.out.println();
    }

    // Utility method to print a specific portion of the array
    public static void printArray(int[] array, int left, int right) {
        System.out.printf("%s", RED);
        for (int i = left; i <= right; i++) {
            
            System.out.print(array[i] + " ");
        }
        System.out.printf("%s", RESET);
        //System.out.println();
    }
}