LeetCode#228 Summary Ranges

Problem Definition:

　　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"].

My Solution:

　　

class Solution:
    # @param {integer[]} nums
    # @return {string[]}
    def summaryRanges(self, nums):
        sr=[]
        n=len(nums)
        if n==0:
            return sr
        start,end=0,0
        p=1
        while p<n:
            if (nums[p]-nums[p-1])>1:
                end=p-1
                if start==end:
                    sr.append(str(nums[start]))
                else:
                    sr.append(str(nums[start])+"->"+str(nums[end]))
                start=p
            p+=1
        end=p-1
        if start==end:
            sr.append(str(nums[start]))
        else:
            sr.append(str(nums[start])+"->"+str(nums[end]))
        return sr

而后在讨论区发现一个短小精悍的写法，显然我对Python太不熟练啦：

def summaryRanges(self, nums):
  ranges, r = [], []
  for n in nums:
    if n-1 not in r:
      r = []
      ranges += r,
    r[1:] = n,
  return ['->'.join(map(str, r)) for r in ranges]

crux：

python的赋值和引用