# 题目描述

# 题目思路

先转换为正整数后，之后一边从小到大逐层求出个十百等数，一边高位到低位逐项累加计算和
注意中间需要先将中间的和设置为long,方便中间进行判断上限，若是超过了上限了，就赋值为0

# 题目解法

/*
* @lc app=leetcode.cn id=7 lang=java
*
* [7] 整数反转
*/
class Solution {
public int reverse(int x) {
if(x >= Integer.MAX_VALUE || x <= Integer.MIN_VALUE || x == 0){
return 0;
}
boolean isContainMulFlag = false;
if(x < 0){
x = 0 - x;
isContainMulFlag = true;
}
long sum = 0;
while(x / 10 != 0){
sum = (sum + x%10)*10;
x = x/10;
if(sum >= Integer.MAX_VALUE){
return 0;
}
}
sum = sum + x;
if(isContainMulFlag){
sum = 0 - sum;
}
if(sum <= Integer.MIN_VALUE){
return 0;
}
return (int)sum;
}
}

class Test{
public static void main(String[]args){
Solution s = new Solution();
int result = s.reverse(-2147483648);
System.out.println(result);
}
}