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2522. Partition String Into Substrings With Values at Most K

Difficulty Topics

Description

You are given a string s consisting of digits from 1 to 9 and an integer k.

A partition of a string s is called good if:

  • Each digit of s is part of exactly one substring.
  • The value of each substring is less than or equal to k.

Return the minimum number of substrings in a good partition of s. If no good partition of s exists, return -1.

Note that:

  • The value of a string is its result when interpreted as an integer. For example, the value of "123" is 123 and the value of "1" is 1.
  • A substring is a contiguous sequence of characters within a string.

 

Example 1:

Input: s = "165462", k = 60
Output: 4
Explanation: We can partition the string into substrings "16", "54", "6", and "2". Each substring has a value less than or equal to k = 60.
It can be shown that we cannot partition the string into less than 4 substrings.

Example 2:

Input: s = "238182", k = 5
Output: -1
Explanation: There is no good partition for this string.

 

Constraints:

  • 1 <= s.length <= 105
  • s[i] is a digit from '1' to '9'.
  • 1 <= k <= 109

 

Solution

partition-string-into-substrings-with-values-at-most-k.py
class Solution:
    def minimumPartition(self, s: str, k: int) -> int:
        N = len(s)
        curr = 0
        res = 0

        for x in s:
            x = int(x)

            curr = curr * 10 + x

            if curr > k:
                res += 1
                curr = x

            if curr > k: return -1

        return res + 1