LeetCode Pascal's Triangle

Description

Given numRows, generate the first numRows of Pascal’s triangle.

For example, given numRows = 5,
Return

[
[1],
[1,1],
[1,2,1],
[1,3,3,1],
[1,4,6,4,1]
]

The original problem is here.

The original code is here.

My Solution

I solve this problem in C++, as below:

/*Pascal's Triangle 
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<vector>
#include<stdlib.h>
using namespace std;

class Solution {
public:
    vector<vector<int>> generate(int numRows) {
        vector<vector<int>> result;
        if(numRows <= 0)
            return result;
        vector<int> oneRow;
        oneRow.push_back(1);
        result.push_back(oneRow);
        if(numRows == 1)
            return result;
            
        for(int i=1;i<numRows;i++){
            vector<int> row;
            int num = 0;
            row.push_back(1);
            for(int j=1;j<i;j++){
                num = result[i-1][j-1] + result[i-1][j];
                row.push_back(num);
            }
            row.push_back(1);
            result.push_back(row);
        }
        return result;
    }
};

Note:

The number at index i of each row(except the begin and the end) is the sum of the numbers at index i-1 and i of the last row.