update 133 java

yennanliu · Oct 2, 2023 · 2cd6010 · 2cd6010
1 parent 4abe53e
commit 2cd6010
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Showing 3 changed files with 83 additions and 4 deletions.
diff --git a/leetcode_java/src/main/java/LeetCodeJava/DFS/NumberOfDistinctIslandSii.java b/leetcode_java/src/main/java/LeetCodeJava/DFS/NumberOfDistinctIslandSii.java
@@ -102,7 +102,4 @@ void dfs(int[][] grid, int x, int y, boolean[][] visited, int ox, int oy, List<L
         }
     }
 
-    public static void main(String[] args) {
-        //System.out.println(true + false);
-    }
 }
diff --git a/leetcode_java/src/main/java/LeetCodeJava/Graph/CloneGraph.java b/leetcode_java/src/main/java/LeetCodeJava/Graph/CloneGraph.java
@@ -39,8 +39,49 @@ public Node(int _val, ArrayList<Node> _neighbors) {
 
 public class CloneGraph {
 
-    // TODO : fix below
     // V0
+    // IDEA : DFS
+    public Node cloneGraph(Node node) {
+
+        // init hashmap
+        // NOTE : hashmap form : <Integer, Node>
+        HashMap<Integer, Node> _visited = new HashMap<>();
+        return _clone(_visited, node);
+    }
+
+    private Node _clone(HashMap<Integer, Node> visited, Node node){
+
+        // NOTE !!! handle edge case, if node is null, return itself directly
+        if (node == null) {
+            return node;
+        }
+
+        int cur_val = node.val;
+
+        //  case 1) already visited, then return hashmap 's value (Node type) directly
+        if (visited.containsKey(cur_val)){
+            return visited.get(cur_val);
+        }
+
+        // NOTE !!! we init copied node as below
+        Node copiedNode = new Node(node.val, new ArrayList());
+        visited.put(cur_val, copiedNode);
+
+        // case 2) node is NOT visited yet, we go through all its neighbors,
+        for (Node _node : node.neighbors){
+            // NOTE !!! op here : we add new copied node to copiedNode.neighbors,
+            //          (e.g. : copiedNode.neighbors.add)
+            //          instead of return it directly
+            copiedNode.neighbors.add(_clone(visited, _node));
+        }
+
+        // NOTE !!! we return copiedNode as final step in code
+        //         -> once code reach here, means all after all recursive call are completed
+        //         -> copiedNode should have all collected nodes
+        return copiedNode;
+    }
+
+    // V0'
 //    Node clonedNode = new Node();
 //    public Node cloneGraph(Node node) {
 //

diff --git a/leetcode_java/src/main/java/dev/workSpace1.java b/leetcode_java/src/main/java/dev/workSpace1.java
@@ -1,6 +1,7 @@
 package dev;
 
 import LeetCodeJava.DataStructure.ListNode;
+import LeetCodeJava.DataStructure.Node;
 import LeetCodeJava.DataStructure.TreeNode;
 
 import java.sql.Array;
@@ -971,4 +972,44 @@ private boolean _is_island(char[][] grid, int x, int y, boolean[][] seen){
         return true;
     }
 
+    // https://leetcode.com/problems/clone-graph/
+    /**
+     *
+     *  if input = [[2,4],[1,3],[2,4],[1,3]]
+     *
+     *  then, _visited :
+     *      {1 : Node(1, List(2, 4)), 2 :  Node(List(1,3)) ...}
+     *
+     */
+    public Node cloneGraph(Node node) {
+
+        // init hashmap
+        HashMap<Integer, Node> _visited = new HashMap<>();
+        return _clone(_visited, node);
+    }
+
+    private Node _clone(HashMap<Integer, Node> visited, Node node){
+
+        if (node == null) {
+            return node;
+        }
+
+
+        int cur_val = node.val;
+
+        if (visited.containsKey(cur_val)){
+            return visited.get(cur_val);
+        }
+
+        Node copiedNode = new Node(node.val, new ArrayList());
+        visited.put(cur_val, copiedNode);
+
+
+        for (Node _node : node.neighbors){
+            copiedNode.neighbors.add(_clone(visited, _node));
+        }
+
+        return copiedNode; // ?
+    }
+
 }