Package g1901_2000.s1946_largest_number_after_mutating_substring

Class Solution

  • public class Solution
extends Object
    1946 - Largest Number After Mutating Substring.

    Medium

    You are given a string num, which represents a large integer. You are also given a 0-indexed integer array change of length 10 that maps each digit 0-9 to another digit. More formally, digit d maps to digit change[d].

    You may choose to mutate a single substring of num. To mutate a substring, replace each digit num[i] with the digit it maps to in change (i.e. replace num[i] with change[num[i]]).

    Return a string representing the largest possible integer after mutating (or choosing not to) a single substring of num.

    A substring is a contiguous sequence of characters within the string.

    Example 1:

    Input: num = “132”, change = [9,8,5,0,3,6,4,2,6,8]

    Output: “832”

    Explanation: Replace the substring “1”:

    • 1 maps to change[1] = 8. Thus, “132” becomes “832”.

    “832” is the largest number that can be created, so return it.

    Example 2:

    Input: num = “021”, change = [9,4,3,5,7,2,1,9,0,6]

    Output: “934”

    Explanation: Replace the substring “021”:

    • 0 maps to change[0] = 9.

    • 2 maps to change[2] = 3.

    • 1 maps to change[1] = 4.

    Thus, “021” becomes “934”.

    “934” is the largest number that can be created, so return it.

    Example 3:

    Input: num = “5”, change = [1,4,7,5,3,2,5,6,9,4]

    Output: “5”

    Explanation: “5” is already the largest number that can be created, so return it.

    Constraints:

    • 1 <= num.length <= 105
    • num consists of only digits 0-9.
    • change.length == 10
    • 0 <= change[d] <= 9

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • maximumNumber

        public String maximumNumber​(String num,
                            int[] change)