Pascal's Triangle II
【題目】
Given a non-negative index k where k ≤ 33, return the kth index row of the Pascal's triangle.
Note that the row index starts from 0.
(翻譯:給定一個非負索引 k,其中 k ≤ 33,返回楊輝三角的第 k 行。)
In Pascal's triangle, each number is the sum of the two numbers directly above it.
(在楊輝三角中,每個數是它左上方和右上方的數的和。)
Example:
Input: 3
Output: [1,3,3,1]
【分析】
只是我上一篇博客題目的簡單變形,此題更爲簡單,還是用ArrayList + 暴力求解,Java實現代碼如下:
class Solution {
public List<Integer> getRow(int rowIndex) {
List<Integer> row = new ArrayList<>();
if (rowIndex < 0) return row;
for (int i = 0; i < rowIndex + 1; i++) {
row.add(0, 1);
for (int j = 1; j < row.size() - 1; j++) {
row.set(j, row.get(j) + row.get(j + 1));
}
}
return row;
}
}