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leetcode-problemset/leetcode-cn/problem (Chinese)/王位继承顺序 [throne-inheritance].html

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2022-03-27 20:45:09 +08:00
<p>一个王国里住着国王、他的孩子们、他的孙子们等等。每一个时间点,这个家庭里有人出生也有人死亡。</p>
<p>这个王国有一个明确规定的王位继承顺序,第一继承人总是国王自己。我们定义递归函数&nbsp;<code>Successor(x, curOrder)</code>&nbsp;,给定一个人&nbsp;<code>x</code>&nbsp;和当前的继承顺序,该函数返回 <code>x</code>&nbsp;的下一继承人。</p>
<pre>
Successor(x, curOrder):
如果 x 没有孩子或者所有 x 的孩子都在 curOrder 中:
如果 x 是国王,那么返回 null
否则,返回 Successor(x 的父亲, curOrder)
否则,返回 x 不在 curOrder 中最年长的孩子
</pre>
<p>比方说,假设王国由国王,他的孩子&nbsp;Alice 和 Bob Alice 比 Bob&nbsp;年长)和 Alice 的孩子&nbsp;Jack 组成。</p>
<ol>
<li>一开始,&nbsp;<code>curOrder</code>&nbsp;&nbsp;<code>["king"]</code>.</li>
<li>调用&nbsp;<code>Successor(king, curOrder)</code>&nbsp;,返回 Alice ,所以我们将 Alice 放入 <code>curOrder</code>&nbsp;中,得到&nbsp;<code>["king", "Alice"]</code>&nbsp;</li>
<li>调用&nbsp;<code>Successor(Alice, curOrder)</code>&nbsp;,返回 Jack ,所以我们将 Jack 放入&nbsp;<code>curOrder</code>&nbsp;中,得到&nbsp;<code>["king", "Alice", "Jack"]</code>&nbsp;</li>
<li>调用&nbsp;<code>Successor(Jack, curOrder)</code>&nbsp;,返回 Bob ,所以我们将 Bob 放入&nbsp;<code>curOrder</code>&nbsp;中,得到&nbsp;<code>["king", "Alice", "Jack", "Bob"]</code>&nbsp;</li>
<li>调用&nbsp;<code>Successor(Bob, curOrder)</code>&nbsp;,返回&nbsp;<code>null</code>&nbsp;。最终得到继承顺序为&nbsp;<code>["king", "Alice", "Jack", "Bob"]</code>&nbsp;</li>
</ol>
<p>通过以上的函数,我们总是能得到一个唯一的继承顺序。</p>
<p>请你实现&nbsp;<code>ThroneInheritance</code>&nbsp;类:</p>
<ul>
<li><code>ThroneInheritance(string kingName)</code> 初始化一个&nbsp;<code>ThroneInheritance</code>&nbsp;类的对象。国王的名字作为构造函数的参数传入。</li>
<li><code>void birth(string parentName, string childName)</code>&nbsp;表示&nbsp;<code>parentName</code>&nbsp;新拥有了一个名为&nbsp;<code>childName</code>&nbsp;的孩子。</li>
<li><code>void death(string name)</code>&nbsp;表示名为&nbsp;<code>name</code>&nbsp;的人死亡。一个人的死亡不会影响&nbsp;<code>Successor</code>&nbsp;函数,也不会影响当前的继承顺序。你可以只将这个人标记为死亡状态。</li>
<li><code>string[] getInheritanceOrder()</code>&nbsp;返回 <strong>除去</strong>&nbsp;死亡人员的当前继承顺序列表。</li>
</ul>
<p>&nbsp;</p>
<p><strong>示例:</strong></p>
<pre>
<strong>输入:</strong>
["ThroneInheritance", "birth", "birth", "birth", "birth", "birth", "birth", "getInheritanceOrder", "death", "getInheritanceOrder"]
[["king"], ["king", "andy"], ["king", "bob"], ["king", "catherine"], ["andy", "matthew"], ["bob", "alex"], ["bob", "asha"], [null], ["bob"], [null]]
<strong>输出:</strong>
[null, null, null, null, null, null, null, ["king", "andy", "matthew", "bob", "alex", "asha", "catherine"], null, ["king", "andy", "matthew", "alex", "asha", "catherine"]]
<strong>解释:</strong>
ThroneInheritance t= new ThroneInheritance("king"); // 继承顺序:<strong>king</strong>
t.birth("king", "andy"); // 继承顺序king &gt; <strong>andy</strong>
t.birth("king", "bob"); // 继承顺序king &gt; andy &gt; <strong>bob</strong>
t.birth("king", "catherine"); // 继承顺序king &gt; andy &gt; bob &gt; <strong>catherine</strong>
t.birth("andy", "matthew"); // 继承顺序king &gt; andy &gt; <strong>matthew</strong> &gt; bob &gt; catherine
t.birth("bob", "alex"); // 继承顺序king &gt; andy &gt; matthew &gt; bob &gt; <strong>alex</strong> &gt; catherine
t.birth("bob", "asha"); // 继承顺序king &gt; andy &gt; matthew &gt; bob &gt; alex &gt; <strong>asha</strong> &gt; catherine
t.getInheritanceOrder(); // 返回 ["king", "andy", "matthew", "bob", "alex", "asha", "catherine"]
t.death("bob"); // 继承顺序king &gt; andy &gt; matthew &gt; <strong>bob已经去世</strong>&gt; alex &gt; asha &gt; catherine
t.getInheritanceOrder(); // 返回 ["king", "andy", "matthew", "alex", "asha", "catherine"]
</pre>
<p>&nbsp;</p>
<p><strong>提示:</strong></p>
<ul>
<li><code>1 &lt;= kingName.length, parentName.length, childName.length, name.length &lt;= 15</code></li>
<li><code>kingName</code><code>parentName</code>&nbsp;<code>childName</code>&nbsp;&nbsp;<code>name</code>&nbsp;仅包含小写英文字母。</li>
<li>所有的参数&nbsp;<code>childName</code>&nbsp;<code>kingName</code>&nbsp;<strong>互不相同</strong></li>
<li>所有&nbsp;<code>death</code>&nbsp;函数中的死亡名字 <code>name</code>&nbsp;要么是国王,要么是已经出生了的人员名字。</li>
<li>每次调用 <code>birth(parentName, childName)</code> 时,测试用例都保证 <code>parentName</code> 对应的人员是活着的。</li>
<li>最多调用&nbsp;<code>10<sup>5</sup></code>&nbsp;<code>birth</code>&nbsp;<code>death</code>&nbsp;</li>
<li>最多调用&nbsp;<code>10</code>&nbsp;&nbsp;<code>getInheritanceOrder</code>&nbsp;</li>
</ul>