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

#include<iostream>#include<vector>using namespace std;class Solution {public:    vector<vector<int> > generate(int numRows) {        int i;        vector<vector<int> > vec(numRows);        for(i=0;i<numRows;i++)           vec[i]=getRow(i);        return vec;    }    vector<int> getRow(int rowIndex) {        if(rowIndex==0)            return {1};        vector<int> vec1(rowIndex);        vector<int> vec2(rowIndex+1);        vec1=getRow(rowIndex-1);        vec2[0]=1;        for(int i=1;i<rowIndex;i++)        {            vec2[i]=vec1[i-1]+vec1[i];        }        vec2[rowIndex]=1;        return vec2;    }};int main(){    Solution s;    int n;    cout<<"input n is :";    cin>>n;    vector<vector<int> > vec=s.generate(n);    for(auto v:vec)    {        for(auto a:v)            cout<<a<<" ";        cout<<endl;    }    cout<<endl;}