minimum-insertion-steps-to-make-a-string-palindrome

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Algorithms

Given a string <code>s</code>. In one step you can insert any character at any index of the string.

Return the minimum number of steps to make <code>s</code>&nbsp;palindrome.

A&nbsp;Palindrome String&nbsp;is one that reads the same backward as well as forward.

&nbsp;
Example 1:

<pre>
Input: s = &quot;zzazz&quot;
Output: 0
Explanation: The string &quot;zzazz&quot; is already palindrome we do not need any insertions.
</pre>

Example 2:

<pre>
Input: s = &quot;mbadm&quot;
Output: 2
Explanation: String can be &quot;mbdadbm&quot; or &quot;mdbabdm&quot;.
</pre>

Example 3:

<pre>
Input: s = &quot;leetcode&quot;
Output: 5
Explanation: Inserting 5 characters the string becomes &quot;leetcodocteel&quot;.
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= s.length &lt;= 500</code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

第 170 场周赛

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minInsertions

首席工程师

Minimum Insertion Steps to Make a String Palindrome

Minimum Number of Moves to Make Palindrome

minimum-number-of-moves-to-make-palindrome

得到回文串的最少操作次数

String

Dynamic Programming

给你一个字符串&nbsp;<code>s</code>&nbsp;，每一次操作你都可以在字符串的任意位置插入任意字符。

请你返回让&nbsp;<code>s</code>&nbsp;成为回文串的&nbsp;最少操作次数&nbsp;。

「回文串」是正读和反读都相同的字符串。

&nbsp;

示例 1：

<pre>
输入：s = "zzazz"
输出：0
解释：字符串 "zzazz" 已经是回文串了，所以不需要做任何插入操作。
</pre>

示例 2：

<pre>
输入：s = "mbadm"
输出：2
解释：字符串可变为 "mbdadbm" 或者 "mdbabdm" 。
</pre>

示例 3：

<pre>
输入：s = "leetcode"
输出：5
解释：插入 5 个字符后字符串变为 "leetcodocteel" 。
</pre>

&nbsp;

提示：

<ul>
	<li><code>1 &lt;= s.length &lt;= 500</code></li>
	<li><code>s</code>&nbsp;中所有字符都是小写字母。</li>
</ul>