append-characters-to-string-to-make-subsequence

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Algorithms

You are given two strings <code>s</code> and <code>t</code> consisting of only lowercase English letters.

Return the minimum number of characters that need to be appended to the end of <code>s</code> so that <code>t</code> becomes a subsequence of <code>s</code>.

A subsequence is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.

&nbsp;
Example 1:

<pre>
Input: s = &quot;coaching&quot;, t = &quot;coding&quot;
Output: 4
Explanation: Append the characters &quot;ding&quot; to the end of s so that s = &quot;coachingding&quot;.
Now, t is a subsequence of s (&quot;coachingding&quot;).
It can be shown that appending any 3 characters to the end of s will never make t a subsequence.
</pre>

Example 2:

<pre>
Input: s = &quot;abcde&quot;, t = &quot;a&quot;
Output: 0
Explanation: t is already a subsequence of s (&quot;abcde&quot;).
</pre>

Example 3:

<pre>
Input: s = &quot;z&quot;, t = &quot;abcde&quot;
Output: 5
Explanation: Append the characters &quot;abcde&quot; to the end of s so that s = &quot;zabcde&quot;.
Now, t is a subsequence of s (&quot;zabcde&quot;).
It can be shown that appending any 4 characters to the end of s will never make t a subsequence.
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= s.length, t.length &lt;= 105</code></li>
	<li><code>s</code> and <code>t</code> consist only of lowercase English letters.</li>
</ul>

appendCharacters

Append Characters to String to Make Subsequence

Is Subsequence

is-subsequence

判断子序列

Minimum Operations to Make a Subsequence

minimum-operations-to-make-a-subsequence

得到子序列的最少操作次数

Greedy

Two Pointers

String

给你两个仅由小写英文字母组成的字符串 <code>s</code> 和 <code>t</code> 。

现在需要通过向 <code>s</code> 末尾追加字符的方式使 <code>t</code> 变成 <code>s</code> 的一个 子序列 ，返回需要追加的最少字符数。

子序列是一个可以由其他字符串删除部分（或不删除）字符但不改变剩下字符顺序得到的字符串。

&nbsp;

示例 1：

<pre>
输入：s = "coaching", t = "coding"
输出：4
解释：向 s 末尾追加字符串 "ding" ，s = "coachingding" 。
现在，t 是 s ("coachingding") 的一个子序列。
可以证明向 s 末尾追加任何 3 个字符都无法使 t 成为 s 的一个子序列。
</pre>

示例 2：

<pre>
输入：s = "abcde", t = "a"
输出：0
解释：t 已经是 s ("abcde") 的一个子序列。
</pre>

示例 3：

<pre>
输入：s = "z", t = "abcde"
输出：5
解释：向 s 末尾追加字符串 "abcde" ，s = "zabcde" 。
现在，t 是 s ("zabcde") 的一个子序列。 
可以证明向 s 末尾追加任何 4 个字符都无法使 t 成为 s 的一个子序列。
</pre>

&nbsp;

提示：

<ul>
	<li><code>1 &lt;= s.length, t.length &lt;= 105</code></li>
	<li><code>s</code> 和 <code>t</code> 仅由小写英文字母组成</li>
</ul>