【LeetCode】119. Pascal's Triangle II QuestionEditorial Solution 解题小结

题目：

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

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

思路大概是一步一步从后往前算出每行的各个元素。

class Solution {
public:
    vector<int> getRow(int rowIndex)  {
        vector<int> pasTrianPre(rowIndex+1, 1);
        for ( int i = 2; i <= rowIndex; i++){
            for ( int j = i-1; j > 0; j--){
                pasTrianPre[j]=pasTrianPre[j-1]+pasTrianPre[j];
            }
        }
        return pasTrianPre;
    }
};