Overview

The objective is to find the print n number of rows of Pascal’s triangle. The number n is given as an input to the program

Example 1

Input: numRows = 4
Output: [[1],[1,1],[1,2,1],[1,3,3,1]]

Example 2

Input: numRows = 5
Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]

Refer to this link to know more about Pascal’s Triangle here – https://en.wikipedia.org/wiki/Pascal%27s_triangle

The idea is to use dynamic programming here.

Program

Below is the program for the same

package main

import "fmt"

func generate(numRows int) [][]int {
	firstRow := []int{1}

	if numRows == 1 {
		return [][]int{firstRow}
	}

	secondRow := []int{1, 1}

	if numRows == 2 {
		return [][]int{firstRow, secondRow}
	}

	output := [][]int{firstRow, secondRow}

	for i := 2; i < numRows; i++ {
		temp := make([]int, i+1)

		lastRow := output[i-1]

		temp[0] = 1
		temp[i] = 1

		for j := 1; j < i; j++ {
			temp[j] = lastRow[j-1] + lastRow[j]
		}

		output = append(output, temp)

	}

	return output

}

func main() {
	output := generate(4)
	fmt.Println(output)

	output = generate(5)
	fmt.Println(output)
}

Output:

[1] [1 1] [1 2 1] [1 3 3 1]]
[[1] [1 1] [1 2 1] [1 3 3 1] [1 4 6 4 1]]

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