splitting-a-string-into-descending-consecutive-values

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1849. Splitting a String Into Descending Consecutive Values (Medium)

You are given a string s that consists of only digits.

Check if we can split s into two or more non-empty substrings such that the numerical values of the substrings are in descending order and the difference between numerical values of every two adjacentsubstrings is equal to 1.

• For example, the string s = "0090089" can be split into ["0090", "089"] with numerical values [90,89]. The values are in descending order and adjacent values differ by 1, so this way is valid.
• Another example, the string s = "001" can be split into ["0", "01"], ["00", "1"], or ["0", "0", "1"]. However all the ways are invalid because they have numerical values [0,1], [0,1], and [0,0,1] respectively, all of which are not in descending order.

Return trueif it is possible to splits​​​​​​ as described above, or false otherwise.

A substring is a contiguous sequence of characters in a string.

 

Example 1:

Input: s = "1234" Output: false Explanation: There is no valid way to split s. 

Example 2:

Input: s = "050043" Output: true Explanation: s can be split into ["05", "004", "3"] with numerical values [5,4,3]. The values are in descending order with adjacent values differing by 1. 

Example 3:

Input: s = "9080701" Output: false Explanation: There is no valid way to split s. 

 

Constraints:

• 1 <= s.length <= 20
• s only consists of digits.

Related Topics

[String] [Backtracking]

Hints

Hint 1

One solution is to try all possible splits using backtrack

Hint 2

Look out for trailing zeros in string