118. 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]
]

class Solution {
public:
vector<vector<int>> generate(int numRows) {
vector<vector<int>> v ;

for(int i = 0; i < numRows; ++i){
v.push_back(vector<int>(i+1,1)); //!!!!!!!!!!!!!!!!!!!!!!
for(int j = 1; j < i; ++j){
v[i][j] = v[i-1][j-1] + v[i-1][j];
}
}
return v;

}
};