Split Message Based on Limit — LeetCode 2468 Python Solution

The problem

You are given a string, message, and a positive integer, limit. You must split message into one or more parts based on limit.

Example

Input

message = "this is really a very awesome message", limit = 9

Output

["thi<1/14>","s i<2/14>","s r<3/14>","eal<4/14>","ly <5/14>","a v<6/14>","ery<7/14>"," aw<8/14>","eso<9/14>","me<10/14>"," m<11/14>","es<12/14>","sa<13/14>","ge<14/14>"]

Explanation

The first 9 parts take 3 characters each from the beginning of message.

Python solution

class Solution:
    def splitMessage(self, message: str, limit: int) -> List[str]:
        n = len(message)
        sa = 0
        for k in range(1, n + 1):
            sa += len(str(k))
            sb = len(str(k)) * k
            sc = 3 * k
            if limit * k - (sa + sb + sc) >= n:
                ans = []
                i = 0
                for j in range(1, k + 1):
                    tail = f'<{j}/{k}>'
                    t = message[i : i + limit - len(tail)] + tail
                    ans.append(t)
                    i += limit - len(tail)
                return ans
        return []

Complexity

Pattern: Monotonic Stack

Answer "what is the next greater element" for every position in one pass. LeetCode 2468. Split Message Based on Limit is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The monotonic stack guide has the Python template for the pattern and the 225 LeetCode problems that use it.

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