20220412.md

Algorithm

7. Reverse Integer

Description

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0.

Assume the environment does not allow you to store 64-bit integers (signed or unsigned).

Example 1:

Input: x = 123
Output: 321

Example 2:

Input: x = -123
Output: -321

Example 3:

Input: x = 120
Output: 21

Constraints:

• -231 <= x <= 231 - 1

Solution

class Solution {
    public int reverse(int x) {
        long sum = 0;
        while(x!=0){
            sum=sum*10+x%10;
            x/=10;
        }
        if(sum>Integer.MAX_VALUE||sum<Integer.MIN_VALUE){
            return 0;
        }
        return (int)sum;
    }
}

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