[LeetCode] DP - 118. Pascal's Triangle

문제

Given an integer numRows, return the first numRows of Pascal's triangle.

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

 

Example 1:

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

Example 2:

Input: numRows = 1
Output: [[1]]

 

Constraints:

• 1 <= numRows <= 30

코드

var generate = function(numRows) {
    let i = 0
    let j = 0;
    let result = [];

    for(let i = 0; i < numRows; i++) {
        const arr = new Array(i + 1)
        result.push(arr);
        for(let j = 0; j <= i; j++) {
            if(j === 0 || j === i) {
                result[i][j] = 1
            } else {
                result[i][j] = result[i - 1][j - 1] + result[i - 1][j]
            }
        }
    }

    return result;
}