diff --git a/kotlin/684-Redundant-Connection.kt b/kotlin/684-Redundant-Connection.kt
new file mode 100644
index 000000000..56cfa9be2
--- /dev/null
+++ b/kotlin/684-Redundant-Connection.kt
@@ -0,0 +1,57 @@
+class Solution {
+    fun findRedundantConnection(edges: Array<IntArray>): IntArray {
+        val uf = UnionFind(edges.size)
+
+        for (edge in edges) {
+            val (u, v) = edge
+
+            if (uf.isConnected(u-1, v-1))
+                return intArrayOf(u, v)
+
+            uf.unify(u-1, v-1)
+        }
+
+        return intArrayOf(0)
+    }
+}
+
+class UnionFind(n : Int) {
+    val parent = IntArray(n) { it }
+    val rank = IntArray(n) { 1 }
+
+    fun unify(p: Int, q: Int) {
+        val rootP = find(p)
+        val rootQ = find(q)
+
+        if (rootP == rootQ)
+            return
+
+        if (rank[rootP] > rank[rootQ]) {
+            parent[rootQ] = parent[rootP]
+            rank[rootP] += rank[rootQ]
+        } else {
+            parent[rootP] = parent[rootQ]
+            rank[rootQ] += rank[rootP]
+        }
+    }
+
+    fun find(p: Int): Int {
+        var root = p
+        var curr = p
+
+        while (root != parent[root])
+            root = parent[root]
+
+        while (root != curr) {
+            val next = parent[curr]
+            parent[p] = parent[root]
+            curr = next
+        }
+
+        return root
+    }
+
+    fun isConnected(p: Int, q: Int): Boolean {
+        return find(p) == find(q)
+    }
+}
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