119.杨辉三角 II

🚌递归实现

class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<vector<int> > vec;
        for(int i = 0; i <= rowIndex; ++i)
        {
            vec.push_back({});
            for(int j = 0; j <= i; ++j)
            {
                vec[i].push_back(helper(i, j, vec));
            }
        }
        return vec[rowIndex];
    }
    int helper(int i, int j, vector<vector<int >>& vec)
    {
        if(j == 0 || i == j)
            return 1;
        return vec[i - 1][j - 1] + vec[i - 1][j];
    }
};

Accepted

34/34 cases passed (0 ms)

Your runtime beats 100 % of cpp submissions

Your memory usage beats 5.16 % of cpp submissions (9 MB)