[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]
]

Hide Tags

 Array

 

 

class Solution {
    public:
        vector<vector<int> > generate(int numRows) {
            vector<vector<int> >  res;
            if(numRows == 0)
                return res;
            vector<int> curLine;
            curLine.push_back(1);
            res.push_back(curLine);

            for(int i = 1; i < numRows; i++)
            {   
                curLine.clear();
                for(int j = 0; j < res[i-1].size(); j++)
                {   
                    if(j == 0)
                        curLine.push_back(1);
                    else
                        curLine.push_back(res[i-1][j-1] + res[i-1][j]);
                }   
                curLine.push_back(1);
                res.push_back(curLine);
            }
            return res;
        }
};