LeetCode:Summary Ranges

问题描述：

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"].

思路：

两个指针 s,e .  如果nums[e+1] = nums[e]+1, 就移动end指针, 否则, 插入字符串nums[s]->nums[e].

java代码：

public class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> res = new ArrayList<String>();
        if(nums == null || nums.length < 1){
            return res;
        }
        int s = 0,e = 0;
        while(e < nums.length){
            if(e + 1 < nums.length && nums[e + 1] == nums[e] + 1){
                ++e;
            }
            else{
                    if(s == e){
                        res.add(Integer.toString(nums[s]));
                    }
                    else{
                        String str = nums[s] + "->" + nums[e];  
                        res.add(str);  
                    }
                    ++e;
                    s = e;
                }
        }
        return res;
    }
}