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Leetcode
Medium
Math
Combinatorics
Simulation
Count Symmetric Integers
Count how many integers in a range have an even number of digits and equal digit sums in both halves.
Acceptance 0%
Problem Statement
Given two integers low and high, count how many integers x in the inclusive range [low, high] are symmetric.
An integer is symmetric when:
- it has an even number of digits, and
- the sum of the first half of its digits is equal to the sum of the second half of its digits.
For example, 1230 is symmetric because 1 + 2 = 3 + 0.
Return the total number of symmetric integers in the range.
Input Format
- Two integers
lowandhighrepresenting the inclusive range. 1 <= low <= high.
Output Format
- Return a single integer: the count of symmetric integers in
[low, high].
Constraints
- Only numbers with an even number of digits can be symmetric.
- The range is inclusive.
- A number is evaluated by its decimal representation without leading zeros.
Examples
Sample cases returned by the problem API.
Example 1
Input
low = 1, high = 100
Output
9
Explanation
The symmetric integers are 11, 22, 33, 44, 55, 66, 77, 88, and 99.
Example 2
Input
low = 1200, high = 1230
Output
4
Explanation
The symmetric integers in this range are 1203, 1212, 1221, and 1230.
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