Leetcode: 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?
分析:细节实现题。代码如下:
class Solution { public: vector<int> getRow(int rowIndex) { if(rowIndex == 0) return vector<int>(1,1); vector<int> result(2,1); for(int i = 3; i <= rowIndex+1; i++){ vector<int> next; next.push_back(1); for(int j = 1; j < i-1; j++){ next.push_back(result[j-1] + result[j]); } next.push_back(1); result = next; } return result; } };