118 Pascal’s Triangle
* 题目描述:Given numRows, generate the first numRows of Pascal’s triangle.
For example, given numRows = 5,
[
[1],
[1,1],
[1,2,1],
[1,3,3,1],
[1,4,6,4,1]
]
题目大意:输入一个行数,产生前n行的Pascal’s triangle.
代码:
package Array; import java.util.ArrayList; import java.util.List; public class Solution { public List<List<Integer>> generate(int numRows) { List<List<Integer>> allrows = new ArrayList<>(); List<Integer> row = new ArrayList<>(); for(int i=0;i<numRows;i++) { row.add(0, 1); for(int j=1;j<row.size()-1;j++) { row.set(j, row.get(j) + row.get(j + 1)); } allrows.add(new ArrayList<>(row)); } return allrows; }