Pascal's Triangle

Description

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

Code

class Solution {
public:
    vector<vector<int>> generate(int numRows) {
        vector<vector<int>> answer(numRows);
 
        for(int i = 0; i < numRows; i++) {
            answer[i].resize(i + 1);
            answer[i][0] = answer[i][i] = 1;
 
            for(int j = 1; j < i; j++) {
                answer[i][j] = answer[i-1][j-1] + answer[i-1][j];
            }
        }
 
        return answer;
    }
};

Source

• Pascal’s Triangle - LeetCode