LeetCode 119：Pascal's Triangle II

Given an index k, return the kth row of the Pascal‘s triangle.

For example, given k = 3,
Return [1,3,3,1].

题目要求计算杨辉三角某一行的元素。这个也是二项式系数的计算问题。

class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> result;
		vector<int> tmp;
		result.push_back(1);
		if (rowIndex <= 0)
			return result;
		
		for (int i=1; i<=rowIndex; i++)
		{
			tmp=result;
			result.clear();
			result.push_back(1);
			for (int i=0; i<tmp.size()-1; i++)
			{
				result.push_back(tmp[i] + tmp[i+1]);
			}
			result.push_back(1);
				
		}
		return result;
    }
};