<p>You are given a string <code>s</code> containing lowercase letters and an integer <code>k</code>. You need to :</p>

<ul>
	<li>First, change some characters of <code>s</code> to other lowercase English letters.</li>
	<li>Then divide <code>s</code> into <code>k</code> non-empty disjoint substrings such that each substring is a palindrome.</li>
</ul>

<p>Return <em>the minimal number of characters that you need to change to divide the string</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;abc&quot;, k = 2
<strong>Output:</strong> 1
<strong>Explanation:</strong>&nbsp;You can split the string into &quot;ab&quot; and &quot;c&quot;, and change 1 character in &quot;ab&quot; to make it palindrome.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;aabbc&quot;, k = 3
<strong>Output:</strong> 0
<strong>Explanation:</strong>&nbsp;You can split the string into &quot;aa&quot;, &quot;bb&quot; and &quot;c&quot;, all of them are palindrome.</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;leetcode&quot;, k = 8
<strong>Output:</strong> 0
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= k &lt;= s.length &lt;= 100</code>.</li>
	<li><code>s</code> only contains lowercase English letters.</li>
</ul>

class Solution {
public:
    unordered_map<string,int> hmap;
    int findChange(string s){
        int cnt = 0;
        for(int i=0;i<s.size()/2;i++){
            if(s[i]!=s[s.size()-1-i]){
                cnt++;
            }
        }
        return cnt;
    }
    int palindromePartition(string s, int k) {
        if(k==s.size())
            return 0;
        if(k>s.size()){
            return 10001;
        }
        if(hmap.find(s+to_string(k))!=hmap.end())
            return hmap[s+to_string(k)];
        int mn = INT_MAX;
        for(int i=0;i<s.size();i++){
            string sub = s.substr(0,i+1);
            string rem = s.substr(i+1,s.size()-(i+1));
            int cnt = findChange(sub);
            mn = min(mn, cnt+palindromePartition(rem,k-1));
        }
        return hmap[s+to_string(k)]=mn;
    }
};
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