LeetCode in Kotlin
118. Pascal’s Triangle
Easy
Given an integer numRows, return the first numRows of Pascal’s triangle.
In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown:
Example 1:
Input: numRows = 5
Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]
Example 2:
Input: numRows = 1
Output: [[1]]
Constraints:
1 <= numRows <= 30
Solution
class Solution {
fun generate(numRows: Int): List<List<Int>> {
val output: MutableList<List<Int>> = ArrayList()
for (i in 0 until numRows) {
val currRow: MutableList<Int> = ArrayList()
for (j in 0..i) {
if (j == 0 || j == i || i <= 1) {
currRow.add(1)
} else {
val currCell = output[i - 1][j - 1] + output[i - 1][j]
currRow.add(currCell)
}
}
output.add(currRow)
}
return output
}
}