[LeetCode]题解(python):093 Restore IP Addresses
题目来源
https://leetcode.com/problems/restore-ip-addresses/
Given a string containing only digits, restore it by returning all possible valid IP address combinations.
For example:
Given "25525511135"
,
return ["255.255.11.135", "255.255.111.35"]
. (Order does not matter)
题意分析
Input:一串数字
Output:可能的ip
Conditions:符合0~255
题目思路
用dfs,要注意考虑0.0.0.0的情况,不考虑00.00.00.00这样多个0的
AC代码(Python)
class Solution(object):
def restoreIpAddresses(self, s):
"""
:type s: str
:rtype: List[str]
"""
def dfs(s, sub, ips, ip):
if sub == 4:
if s == "":
ips.append(ip[1:])
return
for i in range(1,4):
if i <= len(s):
if int(s[:i]) <= 255:
dfs(s[i:], sub + 1, ips, ip+"."+s[:i])
if s[0] == "":
break
ips = []
dfs(s, 0, ips, "")
return ips
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