Difficulty: Easy
Given a non-negative integer numRows, generate the first numRows of Pascal’s triangle.
In Pascal’s triangle, each number is the sum of the two numbers directly above it.
Example:
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| Input: 5
Output:
[
[1],
[1,1],
[1,2,1],
[1,3,3,1],
[1,4,6,4,1]
]
|
Solution
Language: Java
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| class Solution {
public List<List<Integer>> generate(int numRows) {
List<List<Integer>> result = new ArrayList<>();
if (numRows <= 0) {
return result;
}
for (int i = 0; i < numRows; i++) {
List<Integer> line = new ArrayList<>();
for (int j = 0; j <= i; j++) {
if (j == 0 || j == i) {
line.add(1);
continue;
}
line.add(result.get(i - 1).get(j - 1) + result.get(i - 1).get(j));
}
result.add(line);
}
return result;
}
}
|