Problem 7 Reverse Integer
Language
JavaScript
Java
Description
Given a 32-bit signed integer, reverse digits of an integer.
Example
Input
- 123
- -123
- 123
Output
- 321
- -321
- 21
Explanation
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
Analysis
The biggest problem is to prevent overflow, so we check the origin x
and the answer ans
. If they're bigger than 2^31-1
, print 0
directly.
Besides, we reverse the number x
by read and traverse as string reversed.
Solution
JavaScript
/**
* @param {number} x
* @return {number}
*/
var reverse = function(x) {
if(x === 0) return 0;
Math.abs(x)>(2**31-1)?x=0:x;
let ans='';
let rev = Math.abs(x).toString();
for(var i =0;i<rev.length;i++){
ans += rev[rev.length-i-1]
}
return parseInt(Math.abs(ans)>(2**31-1)?len=0:(x<0?-ans:ans));
};
Java
class Solution {
public int reverse(int x) {
long rev= 0;
while( x != 0){
rev= rev*10 + x % 10;
x= x/10;
if( rev > Integer.MAX_VALUE || rev < Integer.MIN_VALUE)
return 0;
}
return (int) rev;
}
}
- arrow_back#9 palindrome-number
- arrow_forward#1 two-sum