Sum of Root To Leaf Binary Numbers - LeetCode
Solution
class Solution {
func sumRootToLeaf(_ root: TreeNode?) -> Int {
return getLeafString(root, value: []).map { (num) in
return binTodec(number: num)
}.reduce(0, +)
}
func getLeafString(_ root: TreeNode?, value: [Int]) -> [String] {
guard let root = root else {
return []
}
if root.left == nil && root.right == nil {
return [(value + [root.val]).map{ String($0) }.joined()]
} else {
return getLeafString(root.left, value: value + [root.val]) + getLeafString(root.right, value: value + [root.val])
}
}
func binTodec(number num: String) -> Int {
var sum: Int = 0
for c in num {
let str = String(c)
sum = sum * 2 + Int(str)!
}
return sum
}
}
解题思路
递归取出叶子节点的值，转换成十进制相加
