并查集结构code

src/ds/picture/UnionFind.java

@@ -0,0 +1,85 @@
+package ds.picture;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Stack;
+
+/**
+ * 并查集
+ * @author Wen
+ * @date 2022/9/7 23:27
+ */
+public class UnionFind {
+    //集合结构体
+    static class Node<T> {
+        T t;
+
+        public Node(T t) {
+            this.t = t;
+        }
+    }
+
+    static class UnionFindSet<V> {
+
+        //自身代表点指向集合
+        private HashMap<V, Node<V>> nodeHashMap;
+        //每个结构体上层指向存储
+        private HashMap<Node<V>, Node<V>> parentMap;
+        //代表结构体的总节点数
+        private HashMap<Node<V>, Integer> sizeMap;
+
+
+        public UnionFindSet(List<V> iterator) {
+            int size = iterator.size();
+            nodeHashMap = new HashMap<>(size);
+            parentMap = new HashMap<>(size);
+            sizeMap = new HashMap<>(size);
+            for (V v : iterator) {
+                Node<V> node = new Node<>(v);
+                nodeHashMap.put(v, node);
+                parentMap.put(node, node);
+                sizeMap.put(node, 1);
+            }
+        }
+
+        //找代表节点
+        public Node<V> findFather(Node<V> cur) {
+            Stack<Node<V>> stack = new Stack<>();
+            while (parentMap.get(cur) != cur) {
+                stack.push(cur);
+                cur = parentMap.get(cur);
+            }
+            //将从cur出发的链压平，所经过的节点的代表节点都是cur的代表节点
+            while (!stack.isEmpty()) {
+                parentMap.put(stack.pop(), cur);
+            }
+            return cur;
+        }
+
+        //是否拥有同一个代表结点
+        public boolean isSameSet(V a, V b) {
+            if (nodeHashMap.get(a) == null || nodeHashMap.get(b) == null) {
+                return false;
+            }
+            return findFather(nodeHashMap.get(a)) == findFather(nodeHashMap.get(b));
+        }
+
+        //将小集合合并到大集合
+        public void union(V a, V b) {
+            if (nodeHashMap.get(a) == null || nodeHashMap.get(b) == null) {
+                return;
+            }
+            Node<V> aHead = findFather(nodeHashMap.get(a));
+            Node<V> bHead = findFather(nodeHashMap.get(b));
+            if (aHead != bHead) {
+                Node<V> bigHead = sizeMap.get(aHead) > sizeMap.get(bHead) ? aHead : bHead;
+                Node<V> smallHead = bigHead == aHead ? bHead : aHead;
+                parentMap.put(smallHead, bigHead);
+                sizeMap.put(bigHead, sizeMap.get(bigHead) + sizeMap.get(smallHead));
+                sizeMap.remove(smallHead);
+            }
+        }
+    }
+
+
+}