idk oh well

tools/structures/DisjointSet.ts

@@ -0,0 +1,53 @@
+export class DisjointSet<T> {
+    parent: number[]
+    rank: number[]
+    #map: Map<T, number>
+    #mapCount: number
+
+    constructor(elements: Iterable<T> = []) {
+        this.parent = []
+        this.rank = []
+        this.#map = new Map()
+        this.#mapCount = 0
+
+        for (const element of elements) this.makeSet(element)
+    }
+
+    makeSet(element: T) {
+        this.parent.push(this.#mapCount)
+        this.rank.push(0)
+        this.#map.set(element, this.#mapCount)
+        this.#mapCount++
+    }
+
+    find(element: T): number {
+        const index = this.#map.get(element)
+        if (index === undefined) {
+            throw new Error('Element not found')
+        }
+        return this.findIndex(index)
+    }
+
+    private findIndex(index: number): number {
+        if (this.parent[index] !== index) {
+            this.parent[index] = this.findIndex(this.parent[index])
+        }
+        return this.parent[index]
+    }
+
+    union(a: T, b: T) {
+        const aIndex = this.find(a)
+        const bIndex = this.find(b)
+
+        if (aIndex === bIndex) return
+
+        if (this.rank[aIndex] < this.rank[bIndex]) {
+            this.parent[aIndex] = bIndex
+        } else if (this.rank[aIndex] > this.rank[bIndex]) {
+            this.parent[bIndex] = aIndex
+        } else {
+            this.parent[bIndex] = aIndex
+            this.rank[aIndex]++
+        }
+    }
+}