[Array] 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]
]
方法：正常模拟即可。

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

        for(int i=0;i<numRows;i++){
            res[i].resize(i+1);
            res[i][0]=res[i][i]=1;
            for(int j=1;j<i;j++)
                res[i][j]=res[i-1][j-1]+res[i-1][j];
        }

        return res;


    }
};