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"].

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解题思路：

直观思路，判断nums[i]- nums[i-1]是否为1，是就继续，不是就判定范围，存入ArrayList.

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Java code:

public class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> result = new ArrayList<String>();
        if(nums == null || nums.length == 0){
            return result;
        }
        int left = nums[0];
        int right = 0;
        for(int i = 1; i < nums.length; i++){
            if(nums[i] - nums[i-1] != 1){
                right = nums[i-1];
                if(left == right){
                    result.add("" + left);
                }else {
                    result.add(left + "->"+right);
                }
                left = nums[i];
            }
        }
        right = nums[nums.length-1];
        if(left == right){
            result.add("" + left);
        }else {
            result.add(left + "->"+right);
        }
        return result;
    }
}