Create 1061-lexicographically-smallest-equivalent-string.js

Author: everthis

1061-lexicographically-smallest-equivalent-string.js

@@ -0,0 +1,47 @@
+/**
+ * @param {string} s1
+ * @param {string} s2
+ * @param {string} baseStr
+ * @return {string}
+ */
+var smallestEquivalentString = function (s1, s2, baseStr) {
+  if (s1.length === 0 || s2.length === 0) return ''
+  const uf = new UnionFind()
+  for (let i = 0; i < s1.length; i++) {
+    uf.union(s1[i], s2[i])
+  }
+  let res = ''
+  for (const ch of baseStr) {
+    res += uf.find(ch) || ch // some letters don't have connected component
+  }
+  return res
+}
+class UnionFind {
+  constructor() {
+    this.parents = new Map()
+  }
+  find(x) {
+    if (this.parents.get(x) === x) return x
+    this.parents.set(x, this.find(this.parents.get(x))) // path compression
+    return this.parents.get(x)
+  }
+  union(u, v) {
+    // init
+    if (!this.parents.has(u)) {
+      this.parents.set(u, u)
+    }
+    if (!this.parents.has(v)) {
+      this.parents.set(v, v)
+    }
+    // find root
+    const rootU = this.find(u)
+    const rootV = this.find(v)
+    if (rootU === rootV) return // connected already
+    // set smallest lex as the root
+    if (rootU > rootV) {
+      this.parents.set(rootU, rootV)
+    } else {
+      this.parents.set(rootV, rootU)
+    }
+  }
+}