leetcodeブラシ問題、まとめ、記録、メモ119

leetcode119Pascal'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?
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Pascal's Triangle Iと同様に、kのサイズに応じて、対応する反復を行えばよい.

class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> temp, t;
        temp.push_back(1);
        if (rowIndex == 0)
        {
            return temp;
        }
        
        for (int i = 1; i <= rowIndex; ++i)
        {
            temp.push_back(0);
            t = temp;
            for (int j = 1; j <= i; ++j)
            {
                t[j] = temp[j] + temp[j-1];
            }
            temp = t;
        }
        
        return t;
    }
};