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ReverseInteger.java
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ReverseInteger.java
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package dsalgo.leetcode;
/**
* ReverseInteger
* Reverse digits of an integer
*
* @author Umang G
*/
public class ReverseInteger {
/**
* <p>
* {@code ReverseInteger} instance should NOT be constructed in standard
* programming, so its defined as private
* </p>
*/
private ReverseInteger() {
}
/**
* Reverse digits of an integer and return the integer, if result is not in
* 32-bit signed integer then it return 0
*
* @param x integer to be reverse
* @return reversed integer or 0
*/
public static int reverse(int x) {
int reverse = 0;
while (x != 0) {
int pop = x % 10;
x /= 10;
if (reverse > Integer.MAX_VALUE / 10 || (reverse == Integer.MAX_VALUE / 10 && pop > Integer.MAX_VALUE % 10))
return 0;
if (reverse < Integer.MIN_VALUE / 10 || (reverse == Integer.MIN_VALUE / 10 && pop < Integer.MIN_VALUE % 10))
return 0;
reverse = reverse * 10 + pop;
}
return reverse;
}
}
/*
* 7. Reverse Integer (https://leetcode.com/problems/reverse-integer/)
*
* Given a 32-bit signed integer, reverse digits of an integer.
*
* Example 1:
* Input: 123
* Output: 321
* Example 2:
* Input: -123
* Output: -321
* Example 3:
* Input: 120
* Output: 21
*
* Note:
* 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.
*
*/