【leetcode】7. Reverse Integer

 1 public static int reverse(int x) {
 2         String s =""+x;
 3         char[] array=s.toCharArray();
 4         if(array[0]==‘-‘){
 5             reverse(array,1);
 6             Long num=Long.valueOf(new String(array));
 7             if(num<Integer.MIN_VALUE){
 8                 return 0;
 9             }
10             return Integer.valueOf(new String(array));
11             
12         }
13         else{
14             reverse(array,0);
15             Long num=Long.valueOf(new String(array));
16             if(num>Integer.MAX_VALUE){
17                 return 0;
18             }
19             return Integer.valueOf(new String(array));
20         }
21 
22    }
23    public static void reverse(char[] array,int from){
24        int to = array.length-1;
25        while(from<to){
26            char ch=array[from];
27            array[from]=array[to];
28            array[to]=ch;
29            from++;
30            to--;
31        }
32    }