Leetcode - Pascal's Triangle II

题目链接

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?

解题思路

TODO （稍后补充）

解题代码

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