Today I have done leetcode's September LeetCoding Challenge with cpp.

September LeetCoding Challenge 8

Description

Pascal's Triangle

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

Solution

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

// Accepted
// 14/14 cases passed (0 ms)
// Your runtime beats 100 % of cpp submissions
// Your memory usage beats 33.54 % of cpp submissions (6.6 MB)