leetcode#7-Reverse Integer-java

题目：

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

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Note:
The input is assumed to be a 32-bit signed integer. Your 
function should return 0 when the reversed integer 
overflows.

解法：

int start = 0;
if(x<0){
    start = 1;
}
char [] test = String.valueOf(x).toCharArray();
int exp = 0;
int result = 0;
for(int i=start;i'0')*(Math.pow(10,exp));
    exp++;
}
if(result>=Math.pow(2,31)-1){
    return 0;
}
if(start==1){
    result = result-result*2;
}
return result;