Create 2709-greatest-common-divisor-traversal.kt

Author: a93a

kotlin/2709-greatest-common-divisor-traversal.kt

@@ -0,0 +1,59 @@
+class UnionFind (val n: Int) {
+    val parent = IntArray (n) { it }
+    val size = IntArray (n) { 1 }
+    var count = n
+
+    fun find(x: Int): Int {
+        if (x != parent[x])
+            parent[x] = find(parent[x])
+        return parent[x]
+    }
+
+    fun union(x: Int, y: Int) {
+        val px = find(x)
+        val py = find(y)
+        if (px != py) {
+            if (size[px] > size[py]) {
+                parent[py] = px
+                size[px] += size[py]
+            } else {
+                parent[px] = py
+                size[py] += size[px]
+            }
+            count--
+        }
+    }
+}
+
+class Solution {
+    fun canTraverseAllPairs(nums: IntArray): Boolean {
+        val uf = UnionFind (nums.size)
+        val factorIndex = HashMap<Int, Int>()
+
+        for (i in nums.indices) {
+            var n = nums[i]
+            var f = 2
+
+            while (f * f <= n) {
+                if (n % f == 0) {
+                    if (f in factorIndex)
+                        uf.union(i, factorIndex[f]!!)
+                    else
+                        factorIndex[f] = i
+                    while (n % f == 0)
+                        n /= f
+                }
+                f++
+            }
+
+            if (n > 1) {
+                if (n in factorIndex)
+                    uf.union(i, factorIndex[n]!!)
+                else
+                    factorIndex[n] = i
+            }
+        }
+        
+        return uf.count == 1
+    }
+}