You are given an array numbers. Expand the numbers into an a palindrome landscape of mountains. For numbers = [2,3,2,4], palindromeMountains = [1,2,1,2,3,1,2,1,2,3,4,3,2,1]
Example
Input:
numbers = [2,3,2,4]Expected value:
palindromeMountains = [1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 3, 4, 3, 2, 1]
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Hint
Iterate from 1 to number and then back to 1, in decreasing order. Do this for each number and avoid adding 1 twice consecutively.
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Solution
let numbers = [2,3,2,4]
func palindromeSequence(numbers:[Int]) -> [Int] {
var mountains = [Int]()
for i in 0..<numbers.count {
var j = 1
if i != 0 {j = 2}
while j <= numbers[i] {
mountains.append(j)
j += 1
}
j -= 1
repeat {
j -= 1
mountains.append(j)
} while j > 1
}
return mountains
}
var palindromeMountains = palindromeSequence(numbers: numbers)[collapse]
