<p>Given two strings <code>s1</code> and&nbsp;<code>s2</code>, return <em>the lowest <strong>ASCII</strong> sum of deleted characters to make two strings equal</em>.</p>

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

<pre>
<strong>Input:</strong> s1 = &quot;sea&quot;, s2 = &quot;eat&quot;
<strong>Output:</strong> 231
<strong>Explanation:</strong> Deleting &quot;s&quot; from &quot;sea&quot; adds the ASCII value of &quot;s&quot; (115) to the sum.
Deleting &quot;t&quot; from &quot;eat&quot; adds 116 to the sum.
At the end, both strings are equal, and 115 + 116 = 231 is the minimum sum possible to achieve this.
</pre>

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

<pre>
<strong>Input:</strong> s1 = &quot;delete&quot;, s2 = &quot;leet&quot;
<strong>Output:</strong> 403
<strong>Explanation:</strong> Deleting &quot;dee&quot; from &quot;delete&quot; to turn the string into &quot;let&quot;,
adds 100[d] + 101[e] + 101[e] to the sum.
Deleting &quot;e&quot; from &quot;leet&quot; adds 101[e] to the sum.
At the end, both strings are equal to &quot;let&quot;, and the answer is 100+101+101+101 = 403.
If instead we turned both strings into &quot;lee&quot; or &quot;eet&quot;, we would get answers of 433 or 417, which are higher.
</pre>

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

<ul>
	<li><code>1 &lt;= s1.length, s2.length &lt;= 1000</code></li>
	<li><code>s1</code> and <code>s2</code> consist of lowercase English letters.</li>
</ul>

class Solution {
public:
    int solve(string &s1, string &s2, int n, int m,vector<vector<int>>&dp){
        if(n == 0) {
            int res = 0;
            for(int i=0;i < m;i++) res += s2[i];
            return res;
        }
        if(m == 0) {
            int res = 0;
            for(int i=0;i < n;i++) res += s1[i];
            return res;
        }

        if(dp[n][m] != -1) return dp[n][m];

        if(s1[n-1] == s2[m-1]) return dp[n][m] = solve(s1,s2, n-1, m-1,dp);
        return dp[n][m] = min({s2[m-1] + solve(s1,s2, n, m-1,dp),s1[n-1] + solve(s1,s2, n-1, m,dp)});
    }
    int minimumDeleteSum(string s1, string s2) {
        int n = s1.length();
        int m = s2.length();
        vector<vector<int>>dp(n+1, vector<int>(m+1, -1));
        return solve(s1, s2, s1.length() , s2.length(),dp);
    }
};
18100