solve: clone graph

Author: wogha95

clone-graph/wogha95.js

@@ -0,0 +1,68 @@
+/**
+ * TC: O(E)
+ * graph에 연결된 edge만큼 queue에 추가, 제거하며 순회한다.
+ *
+ * SC: O(V + E)
+ * cloned graph만큼 공간 복잡도 생성해야한다.
+ *
+ * V: vertex, E: edge
+ */
+
+/**
+ * // Definition for a _Node.
+ * function _Node(val, neighbors) {
+ *    this.val = val === undefined ? 0 : val;
+ *    this.neighbors = neighbors === undefined ? [] : neighbors;
+ * };
+ */
+
+/**
+ * @param {_Node} node
+ * @return {_Node}
+ */
+var cloneGraph = function (node) {
+  if (!node) {
+    return null;
+  }
+
+  const memory = new Map();
+  const visitedNodeVal = new Set();
+
+  return bfsClone(node);
+
+  // 1. bfs로 순회하면서 deep clone한 graph의 head를 반환
+  function bfsClone(start) {
+    const queue = [start];
+    const clonedHeadNode = new _Node(start.val);
+    memory.set(start.val, clonedHeadNode);
+
+    while (queue.length > 0) {
+      const current = queue.shift();
+      if (visitedNodeVal.has(current.val)) {
+        continue;
+      }
+
+      const clonedCurrentNode = getCloneNode(current.val);
+
+      for (const neighbor of current.neighbors) {
+        const clonedNeighborNode = getCloneNode(neighbor.val);
+        clonedCurrentNode.neighbors.push(clonedNeighborNode);
+
+        queue.push(neighbor);
+      }
+
+      visitedNodeVal.add(current.val);
+    }
+
+    return clonedHeadNode;
+  }
+
+  // 2. memory에 val에 해당하는 node 반환 (없을 경우 생성)
+  function getCloneNode(val) {
+    if (!memory.has(val)) {
+      memory.set(val, new _Node(val));
+    }
+
+    return memory.get(val);
+  }
+};