#leetcode#Summary Ranges

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

For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].




public class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> res = new ArrayList<String>();
        if(nums == null || nums.length == 0)
            return res;
        int start = 0;
        int end = 0;
        
        while(end < nums.length){
            StringBuilder sb = new StringBuilder();
            while(end < nums.length - 1 && nums[end] == nums[end + 1] - 1){
                end ++;
            }
            if(start == end){
                sb.append(nums[start]);
                res.add(sb.toString());
            }else{
                sb.append(nums[start]);
                sb.append("->");
                sb.append(nums[end]);
                res.add(sb.toString());
            }
            end++;
            start = end;
        }
        
        return res;
    }
}