Create 1579-remove-max-number-of-edges-to-keep-graph-fully-traversable.kt

Author: a93a

kotlin/1579-remove-max-number-of-edges-to-keep-graph-fully-traversable.kt

@@ -0,0 +1,63 @@
+class Solution {
+
+    class DSU(val n: Int) {
+        val parent = IntArray(n + 1) {it}
+        val rank = IntArray(n + 1) {1}
+        var components = n
+
+        fun find(x: Int): Int {
+            if (parent[x] != x)
+                parent[x] = find(parent[x])
+            return parent[x]
+        }
+
+        fun union(x: Int, y: Int): Boolean {
+            val pX = find(x)
+            val pY = find(y)
+
+            if (pY == pX)
+                return false
+
+            if (rank[pX] > rank[pY]) {
+                rank[pX] += rank[pY]
+                parent[pY] = pX
+            } else {
+                rank[pY] += rank[pX]
+                parent[pX] = pY
+            }
+
+            components--
+            return true
+        }
+
+        fun connected() = components == 1
+    }
+
+    fun maxNumEdgesToRemove(n: Int, edges: Array<IntArray>): Int {
+        val a = DSU(n)
+        val b = DSU(n)
+
+        var edgeAdded = 0
+        for ((type, u, v) in edges) {
+            if (type == 3) {
+                if (a.union(u, v) or b.union(u, v))
+                        edgeAdded++
+            }
+        }
+
+        for ((type, u, v) in edges) {
+            when (type) {
+                1 -> {
+                    if (a.union(u, v))
+                        edgeAdded++
+                }
+                2 -> {
+                    if (b.union(u, v))
+                        edgeAdded++
+                }
+            }
+        }
+
+        return if (a.connected() && b.connected()) edges.size - edgeAdded else -1
+    }
+}