Leetcode 118 Pascal's Triangle

Leetcode 118 Pascal’s Triangle

#include <vector>using namespace std;class Solution {public:    vector<vector<int>> generate(int numRows) {    vector<vector<int>> triangle;    if(numRows == 0)        return triangle;    vector<int> currentRow(1,1);    vector<int> lastRow;    triangle.push_back(currentRow);    for(int i = 1; i < numRows; i ++)//from 2nd line    {        lastRow = currentRow;        currentRow.clear();        currentRow.push_back(1);        for(int j = 0;j < lastRow.size() - 1;j ++)//number of elements between begin and end = number of lastRow's elements -1        {            currentRow.push_back(lastRow[j]+lastRow[j+1]);//0,1 1,2 2,3        }        currentRow.push_back(1);        triangle.push_back(currentRow);    }    return triangle;    }};