leetcode刷题39

今天刷的题是LeetCode第7题，反转整数

class Solution {
    public int reverse(int x) {
        Long y=0L;
        int returnNum=0;
        while (x!=0){
            int num=x%10;
            y=y*10+num;
            x=x/10;
            }
        if(y>(Math.pow(2,31)-1)||y<-Math.pow(2,31)){
            returnNum=0;
        }else {
            returnNum= Math.toIntExact(y);
        }
        return returnNum;
    }
}