LeetCode: Pascal's Triangle Solution

Approach

Follow this pseudo formula

1currentRow[i] = previousRow[i] + previousRow[i - 1]

Implementation

1var generate = function (numRows) {
2  const res = [[1]]
3
4  for (let rowIndex = 1; rowIndex < numRows; rowIndex++) {
5    const row = Array.from(
6      { length: rowIndex + 1 },
7      (_, elIndex) =>
8        (res[rowIndex - 1][elIndex] || 0) +
9        (res[rowIndex - 1][elIndex - 1] || 0)
10    )
11    res.push(row)
12  }
13
14  return res
15}