#119 - Pascal's Triangle II

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Problem Description

Given an integer rowIndex, return the rowIndexth (0-indexed) row of the Pascal's triangle.

In Pascal's triangle, each number is the sum of the two numbers directly above it as shown:

Solution

/**
 * @param {number} rowIndex
 * @return {number[]}
 */
var getRow = function(rowIndex) {
  return generateTriangle(rowIndex + 1)[rowIndex];
};

function generateTriangle(numRows) {
  const result = [[1]];

  for (let i = 1; i < numRows; i++) {
    result[i] = [1];
    result[i - 1].forEach((value, j, prev) => {
      result[i][j + 1] = (prev[j + 1] + value) || 1;
    });
  }

  return result;
};