Maximum Value after Insertion — LeetCode 1881 Python Solution

The problem

You are given a very large integer n, represented as a string,​​​​​​ and an integer digit x. The digits in n and the digit x are in the inclusive range [1, 9], and n may represent a negative number.

Example

Input

n = "99", x = 9

Output

"999"

Explanation

The result is the same regardless of where you insert 9.

Python solution

class Solution:
    def maxValue(self, n: str, x: int) -> str:
        i = 0
        if n[0] == "-":
            i += 1
            while i < len(n) and int(n[i]) <= x:
                i += 1
        else:
            while i < len(n) and int(n[i]) >= x:
                i += 1
        return n[:i] + str(x) + n[i:]

Complexity

Pattern: Greedy

Take the locally best option every time — when you can prove that never costs you later. LeetCode 1881. Maximum Value after Insertion is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Greedy.

The greedy guide has the Python template for the pattern and the 346 LeetCode problems that use it.

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