Easy Patterns JavaScript

Problem Statement

You are given a number n. You need to generate and print a pattern based on the given value of n.

For each row, starting from the first, print numbers in descending order from n down to 1.
Each number in a row is repeated as many times as the current row index (starting from n).
Instead of printing each row on a new line, separate rows with -1.
Instead of a newline at the end of each row, print -1 to indicate row separation. After printing the entire pattern, end the output with -1.

For n= 3,
pattern: 3 3 3 2 2 2 1 1 1 -1 3 3 2 2 1 1 -1 3 2 1 -1

Solution (JavaScript)

class Solution {
        printPat(n) {
            let output = [];
            for (let row = n; row >= 1; row--) {
                for (let num = n; num >= 1; num--) {
                    for (let count = 1; count <= row; count++) {
                        output.push(num);
                    }
                }
                output.push(-1);
            }
            console.log(output.join(' '));
        }
    }

Explanation

1. **Outer Loop (row)**: This loop runs from `n` down to `1`, representing each row in the pattern. The current row determines how many times each number is repeated.
2. **Middle Loop (num)**: This loop runs from `n` down to `1`, representing each number to be printed in the row.
3. **Inner Loop (count)**: This loop runs from `1` to the current row value, ensuring each number (`num`) is repeated as many times as the current row index.
4. **Row Separation**: After processing all numbers for a row, `-1` is added to the output array to separate rows.
5. **Output**: The collected numbers and separators are joined into a single string and printed.

Notes

This pattern generation problem helps understand nested loops and array manipulation in JavaScript.