medium, Array/String
Question:
给定范围[0,99]的有序整数序列，范围丢失的范围
For example
给定 [0, 1, 3, 50, 75]
返回[“2”, “4->49”, “51->74”, “76->99”]
Qestions by reviewers:
- 序列为空如何处理？
返回["0->99"] - 序列全覆盖如何处理？
返回[]
Solution
问题简单的比较相邻两数即可，由于序列的第一个和最后一个数处于边界，我们可以调价psudo intergers方便处理：-1 和100。问题可以扩展到任意范围。
class Solution(object):
def findMissingRanges(self, vals, start, end):
"""
:type vals: [int]
:type start: int
:type end: int
:rtype: [str]
"""
res = []
pre = start - 1
for i in xrange(len(vals)+1):
cur = end+1 if i == len(vals) else vals[i]
if cur - pre >= 2:
res.append(getRange(pre+1, cur-1))
prv = cur
return res
def getRange(from, to):
"""
:type from: int
:type to: int
:rtype: string
"""
if from == to:
return str(from)
else:
return str(from) + '->' + str(to)
