Question:
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]
]
Anwser 1:
class Solution {
public:
vector<vector<int> > generate(int numRows) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
vector< vector<int> > ret;
for(int i = 0; i < numRows; i++){
vector<int> tmp;
tmp.clear();
if(i == 0) {
tmp.push_back(1);
ret.push_back(tmp);
continue;
}
for(int j = 0; j <= i; j++){
if(j == 0) {
tmp.push_back(1);
} else if(i == j){
tmp.push_back(1);
} else {
tmp.push_back( ret[i-1][j-1] + ret[i-1][j] ); // last row
}
}
ret.push_back(tmp);
}
return ret;
}
};