<p>You are given two strings of the same length <code>s1</code> and <code>s2</code> and a string <code>baseStr</code>.</p> <p>We say <code>s1[i]</code> and <code>s2[i]</code> are equivalent characters.</p> <ul> <li>For example, if <code>s1 = "abc"</code> and <code>s2 = "cde"</code>, then we have <code>'a' == 'c'</code>, <code>'b' == 'd'</code>, and <code>'c' == 'e'</code>.</li> </ul> <p>Equivalent characters follow the usual rules of any equivalence relation:</p> <ul> <li><strong>Reflexivity:</strong> <code>'a' == 'a'</code>.</li> <li><strong>Symmetry:</strong> <code>'a' == 'b'</code> implies <code>'b' == 'a'</code>.</li> <li><strong>Transitivity:</strong> <code>'a' == 'b'</code> and <code>'b' == 'c'</code> implies <code>'a' == 'c'</code>.</li> </ul> <p>For example, given the equivalency information from <code>s1 = "abc"</code> and <code>s2 = "cde"</code>, <code>"acd"</code> and <code>"aab"</code> are equivalent strings of <code>baseStr = "eed"</code>, and <code>"aab"</code> is the lexicographically smallest equivalent string of <code>baseStr</code>.</p> <p>Return <em>the lexicographically smallest equivalent string of </em><code>baseStr</code><em> by using the equivalency information from </em><code>s1</code><em> and </em><code>s2</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> s1 = "parker", s2 = "morris", baseStr = "parser" <strong>Output:</strong> "makkek" <strong>Explanation:</strong> Based on the equivalency information in s1 and s2, we can group their characters as [m,p], [a,o], [k,r,s], [e,i]. The characters in each group are equivalent and sorted in lexicographical order. So the answer is "makkek". </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> s1 = "hello", s2 = "world", baseStr = "hold" <strong>Output:</strong> "hdld" <strong>Explanation: </strong>Based on the equivalency information in s1 and s2, we can group their characters as [h,w], [d,e,o], [l,r]. So only the second letter 'o' in baseStr is changed to 'd', the answer is "hdld". </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> s1 = "leetcode", s2 = "programs", baseStr = "sourcecode" <strong>Output:</strong> "aauaaaaada" <strong>Explanation:</strong> We group the equivalent characters in s1 and s2 as [a,o,e,r,s,c], [l,p], [g,t] and [d,m], thus all letters in baseStr except 'u' and 'd' are transformed to 'a', the answer is "aauaaaaada". </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= s1.length, s2.length, baseStr <= 1000</code></li> <li><code>s1.length == s2.length</code></li> <li><code>s1</code>, <code>s2</code>, and <code>baseStr</code> consist of lowercase English letters.</li> </ul>