ARTS 打卡计划第二周 04/28
Algorithm
Reverse Integer
Given a 32-bit signed integer, reverse digits of an integer.
example1:
Input: 123
Output: 321example2:
Input: -123
Output: -321example3:
Input: 120
Output: 21
Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
package easy;
public class ReverseInteger {
class Solution {
public int reverse(int x) {
int result = 0;
int com = Integer.MAX_VALUE / 10;
char[] str = String.valueOf(x).toCharArray();
char[] newStr = new char[str.length - 1];
for (int i = str.length - 1; i > 0; i--) {
newStr[str.length - 1 - i] = str[i];
}
try {
if (newStr.length == 0) {
return x;
}
//若 start 溢出直接报异常
int start = Integer.valueOf(String.valueOf(newStr));
//保证了 ( start * 10 + end ) <= Integer.MAX_VALUE
if (x >= 0 && start <= com) {
int end = Integer.valueOf(String.valueOf(str[0]));
if (start < com || (start == com && end <= 7)) {
result = start * 10 + end;
}
}
if (x < 0) {
result = -start;
}
return result;
} catch (Exception e) {
//e.printStackTrace();
return 0;
}
}
}
}
提交结果
Review
《Teach Yourself Programming in Ten Years》
- 沉醉编程
- 实践中学习
- 与同行多交流
- 读计科专业
- 与同事一起做项目
- 尝试跟随其他大牛学习
- 至少学会不同类语言各一种
- 深入了解计算机组织与结构
- 语言标准化
- 良好的意识