118. Pascal's Triangle

https://leetcode.com/problems/pascals-triangle/

JavaScript

/**
 * @param {number} numRows
 * @return {number[][]}
 */
function generate(numRows) {
  const result = []
  for (let i = 0; i < numRows; i++) {
    result.push([])
    for (let j = 0; j < i + 1; j++) {
      if (j === 0 || j === i) {
        result[i].push(1)
      } else {
        result[i].push(result[i - 1][j - 1] + result[i - 1][j])
      }
    }
  }
  return result
}

Python

class Solution(object):

    def generate(self, numRows):
        """
        :type numRows: int
        :rtype: List[List[int]]
        """
        result = []
        for i in range(numRows):
            result.append([])
            for j in range(i + 1):
                if j in (0, i):
                    result[i].append(1)
                else:
                    result[i].append(result[i - 1][j - 1] + result[i - 1][j])
        return result

Go

func generate(numRows int) [][]int {
	result := [][]int{}
	for i := 0; i < numRows; i++ {
		row := []int{}
		for j := 0; j < i+1; j++ {
			if j == 0 || j == i {
				row = append(row, 1)
			} else {
				row = append(row, result[i-1][j-1]+result[i-1][j])
			}
		}
		result = append(result, row)
	}
	return result
}