<p>Given two strings <code>s</code> and <code>t</code>, find the number of ways you can choose a non-empty substring of <code>s</code> and replace a <strong>single character</strong> by a different character such that the resulting substring is a substring of <code>t</code>. In other words, find the number of substrings in <code>s</code> that differ from some substring in <code>t</code> by <strong>exactly</strong> one character.</p>

<p>For example, the underlined substrings in <code>&quot;<u>compute</u>r&quot;</code> and <code>&quot;<u>computa</u>tion&quot;</code> only differ by the <code>&#39;e&#39;</code>/<code>&#39;a&#39;</code>, so this is a valid way.</p>

<p>Return <em>the number of substrings that satisfy the condition above.</em></p>

<p>A <strong>substring</strong> is a contiguous sequence of characters within a string.</p>

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

<pre>
<strong>Input:</strong> s = &quot;aba&quot;, t = &quot;baba&quot;
<strong>Output:</strong> 6
<strong>Explanation:</strong> The following are the pairs of substrings from s and t that differ by exactly 1 character:
(&quot;<u>a</u>ba&quot;, &quot;<u>b</u>aba&quot;)
(&quot;<u>a</u>ba&quot;, &quot;ba<u>b</u>a&quot;)
(&quot;ab<u>a</u>&quot;, &quot;<u>b</u>aba&quot;)
(&quot;ab<u>a</u>&quot;, &quot;ba<u>b</u>a&quot;)
(&quot;a<u>b</u>a&quot;, &quot;b<u>a</u>ba&quot;)
(&quot;a<u>b</u>a&quot;, &quot;bab<u>a</u>&quot;)
The underlined portions are the substrings that are chosen from s and t.
</pre>
​​<strong class="example">Example 2:</strong>

<pre>
<strong>Input:</strong> s = &quot;ab&quot;, t = &quot;bb&quot;
<strong>Output:</strong> 3
<strong>Explanation:</strong> The following are the pairs of substrings from s and t that differ by 1 character:
(&quot;<u>a</u>b&quot;, &quot;<u>b</u>b&quot;)
(&quot;<u>a</u>b&quot;, &quot;b<u>b</u>&quot;)
(&quot;<u>ab</u>&quot;, &quot;<u>bb</u>&quot;)
​​​​The underlined portions are the substrings that are chosen from s and t.
</pre>

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

<ul>
	<li><code>1 &lt;= s.length, t.length &lt;= 100</code></li>
	<li><code>s</code> and <code>t</code> consist of lowercase English letters only.</li>
</ul>

class Solution {
public:
    int countSubstrings(string s, string t) {
        int count = 0;
        unordered_map<string, int> mp;

        for (int i = 0; i < s.length(); i++) {
            for (int j = i; j < s.length(); j++) {
                string temp = s.substr(i, j - i + 1);
                
              
                if (mp.find(temp) == mp.end()) {
                    int length = j - i + 1;
                    int tempCount = 0;

                    for (int k = 0; k <= t.length() - length; k++) {
                        string t_sub = t.substr(k, length);
                        int mismatches = 0;

                       
                        for (int l = 0; l < length; l++) {
                            if (temp[l] != t_sub[l]) {
                                mismatches++;
                            }
                            if (mismatches > 1) {
                                break;
                            }
                        }

                        if (mismatches == 1) {
                            tempCount++;
                        }
                    }

                    mp[temp] = tempCount;
                }
                
                count += mp[temp];
            }
        }

        return count;
    }
};

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