Project Notes

Restore IP Addresses

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Description

tab: English
 
<p>A <strong>valid IP address</strong> consists of exactly four integers separated by single dots. Each integer is between <code>0</code> and <code>255</code> (<strong>inclusive</strong>) and cannot have leading zeros.</p>
 
<ul>
	<li>For example, <code>&quot;0.1.2.201&quot;</code> and <code>&quot;192.168.1.1&quot;</code> are <strong>valid</strong> IP addresses, but <code>&quot;0.011.255.245&quot;</code>, <code>&quot;192.168.1.312&quot;</code> and <code>&quot;192.168@1.1&quot;</code> are <strong>invalid</strong> IP addresses.</li>
</ul>
 
<p>Given a string <code>s</code> containing only digits, return <em>all possible valid IP addresses that can be formed by inserting dots into </em><code>s</code>. You are <strong>not</strong> allowed to reorder or remove any digits in <code>s</code>. You may return the valid IP addresses in <strong>any</strong> order.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;25525511135&quot;
<strong>Output:</strong> [&quot;255.255.11.135&quot;,&quot;255.255.111.35&quot;]
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;0000&quot;
<strong>Output:</strong> [&quot;0.0.0.0&quot;]
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;101023&quot;
<strong>Output:</strong> [&quot;1.0.10.23&quot;,&quot;1.0.102.3&quot;,&quot;10.1.0.23&quot;,&quot;10.10.2.3&quot;,&quot;101.0.2.3&quot;]
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length &lt;= 20</code></li>
	<li><code>s</code> consists of digits only.</li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/restore-ip-addresses/submissions/) | [solutions](https://leetcode.com/problems/restore-ip-addresses/solutions/)
 
 
tab: 中文
 
<p><strong>有效 IP 地址</strong> 正好由四个整数（每个整数位于 <code>0</code> 到 <code>255</code> 之间组成，且不能含有前导 <code>0</code>），整数之间用 <code>'.'</code> 分隔。</p>
 
<ul>
	<li>例如：<code>"0.1.2.201"</code> 和<code> "192.168.1.1"</code> 是 <strong>有效</strong> IP 地址，但是 <code>"0.011.255.245"</code>、<code>"192.168.1.312"</code> 和 <code>"192.168@1.1"</code> 是 <strong>无效</strong> IP 地址。</li>
</ul>
 
<p>给定一个只包含数字的字符串 <code>s</code> ，用以表示一个 IP 地址，返回所有可能的<strong>有效 IP 地址</strong>，这些地址可以通过在 <code>s</code> 中插入&nbsp;<code>'.'</code> 来形成。你 <strong>不能</strong>&nbsp;重新排序或删除 <code>s</code> 中的任何数字。你可以按 <strong>任何</strong> 顺序返回答案。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1：</strong></p>
 
<pre>
<strong>输入：</strong>s = "25525511135"
<strong>输出：</strong>["255.255.11.135","255.255.111.35"]
</pre>
 
<p><strong>示例 2：</strong></p>
 
<pre>
<strong>输入：</strong>s = "0000"
<strong>输出：</strong>["0.0.0.0"]
</pre>
 
<p><strong>示例 3：</strong></p>
 
<pre>
<strong>输入：</strong>s = "101023"
<strong>输出：</strong>["1.0.10.23","1.0.102.3","10.1.0.23","10.10.2.3","101.0.2.3"]
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length &lt;= 20</code></li>
	<li><code>s</code> 仅由数字组成</li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/restore-ip-addresses/submissions/) | [题解](https://leetcode.cn/problems/restore-ip-addresses/solution/)

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