- Difficulty: Medium
- Tags: LeetCode, Medium, String, Backtracking, leetcode-842, Array, O(n^3), O(n)
Problem
You are given a string of digits num
, such as "123456579"
. We can split it into a Fibonacci-like sequence [123, 456, 579]
.
Formally, a Fibonacci-like sequence is a list f
of non-negative integers such that:
0 <= f[i] < 231
, (that is, each integer fits in a 32-bit signed integer type),f.length >= 3
, andf[i] + f[i + 1] == f[i + 2]
for all0 <= i < f.length - 2
.
Note that when splitting the string into pieces, each piece must not have extra leading zeroes, except if the piece is the number 0
itself.
Return any Fibonacci-like sequence split from num
, or return []
if it cannot be done.
Example 1:
Input: num = "1101111" Output: [11,0,11,11] Explanation: The output [110, 1, 111] would also be accepted.
Example 2:
Input: num = "112358130" Output: [] Explanation: The task is impossible.
Example 3:
Input: num = "0123" Output: [] Explanation: Leading zeroes are not allowed, so "01", "2", "3" is not valid.
Constraints:
1 <= num.length <= 200
num
contains only digits.