summaryRanges.java

/*
Given a sorted integer array without duplicates, return the summary of its ranges.

Example 1:

Input:  [0,1,2,4,5,7]
Output: ["0->2","4->5","7"]
Explanation: 0,1,2 form a continuous range; 4,5 form a continuous range.
Example 2:

Input:  [0,2,3,4,6,8,9]
Output: ["0","2->4","6","8->9"]
Explanation: 2,3,4 form a continuous range; 8,9 form a continuous range.
*/

public List<String> summaryRanges(int[] nums) {
        ArrayList<Integer> a = new ArrayList<Integer>();
        List<String> result = new ArrayList<String>();
        if(nums.length ==0 || nums ==null)
            return result;
        
        for( int i =0; i<nums.length; i++)
            a.add(nums[i]);
        a.add(Integer.MAX_VALUE);

        int n= a.size();
        
        for( int i =0; i<n-1; i++)
        {
            int start = a.get(i);
            int k=i;
           while(i<n-1&&  a.get(i)+1== a.get(i+1))
           {
               i++;
           }
           if(i==k)
               result.add(String.valueOf(start));
           else
               result.add(String.valueOf(start)+"->"+String.valueOf( a.get(i)));
        }

        return result;
    }