9. Palindrome Number
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.
Follow up: Could you solve it without converting the integer to a string?
Example 1:
Input: x = 121
Output: true
Example 2:
Input: x = -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.
Example 3:
Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.
Example 4:
Input: x = -101
Output: false
Constraints:
-231 <= x <= 231 - 1
# @lc code=start
using LeetCode
function is_palindrome(x::Int)::Bool
if x < 0
false
else
y = x
y_reverse = 0
while y > 0
y, n = divrem(y, 10)
y_reverse = y_reverse * 10 + n
end
x == y_reverse
end
end
# @lc code=end
is_palindrome (generic function with 1 method)
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