Here in my solution,

if I change the result to be long type, I will fail

on this test case

Input:

"9223372036854775809"

Output:

-2147483648

Expected:

2147483647

but Double type works fine?

Can anyone explain the message behind this? thanks

```
public class Solution {
public int myAtoi(String str) {
if (str == null || str.length() < 1)
return 0;
// trim white spaces
str = str.trim();
int sign = 1;
// check negative or positive
int i = 0;
if (str.charAt(0) == '-') {
sign = -1;
i++;
} else if (str.charAt(0) == '+') {
i++;
}
// use double to store result
double result = 0;
// calculate value
while (str.length() > i && str.charAt(i) >= '0' && str.charAt(i) <= '9') {
result = result * 10 + (str.charAt(i) - '0');
i++;
}
result *= sign;
// handle max and min
if (result > Integer.MAX_VALUE)
return Integer.MAX_VALUE;
if (result < Integer.MIN_VALUE)
return Integer.MIN_VALUE;
return (int) result;
}
}
```