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]

.

Note:

Could you optimize your algorithm to use only O(k) extra space?

C++代码：

class Solution {
public:
vector<int> getRow(int rowIndex) {
vector<int> row;
row.push_back(1);
for(int i=0;i<=rowIndex;i++)
{
vector<int> temp_row;
row.push_back(0);
int n=0;
for(int j=0;j<=i;j++)
{
n+=row[j];
temp_row.push_back(n);
n=row[j];
}
row=temp_row;
}
return row;
}
};