4.12 leetcode -12 pascals-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]

]

额。。ptriangle[i] = vector<int>(i + 1);重点是这句，没有变量名的，是可以用的，用变量名，就得push吧

class Solution {public:    vector<vector<int> > generate(int numRows) {        vector<vector<int>> ptriangle(numRows);        for(int i = 0;i < numRows;i++)            {            ptriangle[i] = vector<int>(i + 1);            for(int j = 0;j < (i+1);j++)                {                if(j == 0 || j == (i))                    ptriangle[i][j] = 1;                else                    ptriangle[i][j] = ptriangle[i - 1][j - 1] + ptriangle[i - 1][j];            }        }        return ptriangle;    }};