您的位置:首页 > 其它

119. Pascal's Triangle II

2015-08-12 15:15 337 查看
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:每次计算只和上一层有关系,因此只需要一个数组空间就可以

class Solution {
public:
vector<int> getRow(int rowIndex) {
// IMPORTANT: Please reset any member data you declared, as
// the same Solution instance will be reused for each test case.
vector<int> res(rowIndex+1,1);
if(rowIndex == 0)return res;
for(int i = 1; i <= rowIndex; i++)
{
int tmp = res[0];
for(int j = 1; j <= i-1; j++)
{
int kk = res[j];
res[j] = tmp+res[j];
tmp = kk;
}
}
return res;
}
};
内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签: