118. Pascal's Triangle.cpp

class Solution {
public:
    vector<vector<int>> generate(int numRows) {
        vector<vector<int>>ans(numRows);
        ans[0].push_back(1);
        for (int i=1; i<numRows; ++i){
            ans[i].push_back(1);
            for (int j=1; j<ans[i-1].size(); ++j) {
                ans[i].push_back(ans[i-1][j]+ans[i-1][j-1]);
            }
            ans[i].push_back(1);
        }
        return ans;
    }
};