Leetcode Pascal's Triangle

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]
]

很简单的题不多说，也可以用队列实现

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

typedef vector<vector<int> > VVI;

VVI generate(int numRows){
    VVI res;
    if(numRows == 0) return res;
    vector<int> row;
    row.push_back(1);
    res.push_back(row);
    if(numRows == 1) return res;
    row.push_back(1);
    res.push_back(row);
    if(numRows == 2) return res;
    for(int i = 3; i <= numRows; ++ i){
        vector<int> newRow(i,1);
        for(int j = 1; j < i-1; ++ j){
            newRow[j] = row[j]+row[j-1];
        }
        res.push_back(newRow);
        row = newRow;
    }
    return res;
} 

int main(){
    VVI res = generate(5);
    for(int i = 0 ; i < res.size(); ++ i){
        for(int j = 0 ; j < res[i].size(); ++ j){
            cout<<" "<<res[i][j];
        }
        cout<<endl;
    }
    cout<<endl;
    
}