Time: 120 ms (71.19%), Space: 122.3 MB (64.41%) - LeetHub

Author: Sangram03

3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii/3645-maximize-the-number-of-target-nodes-after-connecting-trees-ii.java

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+import java.util.*;
+
+class Solution {
+    public int[] maxTargetNodes(int[][] edges1, int[][] edges2) {
+        int n = edges1.length + 1;
+        int m = edges2.length + 1;
+
+        List<List<Integer>> tree1 = buildGraph(edges1, n);
+        List<List<Integer>> tree2 = buildGraph(edges2, m);
+
+        int[] color1 = new int[2];
+        int[] nodeColor1 = new int[n];
+        bfs(tree1, color1, nodeColor1);
+
+        int[] color2 = new int[2];
+        int[] nodeColor2 = new int[m];
+        bfs(tree2, color2, nodeColor2);
+
+        int maxColor2 = Math.max(color2[0], color2[1]);
+
+        int[] result = new int[n];
+        for (int i = 0; i < n; i++) {
+            result[i] = color1[nodeColor1[i]] + maxColor2;
+        }
+
+        return result;
+    }
+
+    private List<List<Integer>> buildGraph(int[][] edges, int size) {
+        List<List<Integer>> graph = new ArrayList<>();
+        for (int i = 0; i < size; i++) graph.add(new ArrayList<>());
+        for (int[] edge : edges) {
+            int u = edge[0], v = edge[1];
+            graph.get(u).add(v);
+            graph.get(v).add(u);
+        }
+        return graph;
+    }
+
+    private void bfs(List<List<Integer>> graph, int[] colorCount, int[] nodeColor) {
+        int n = graph.size();
+        boolean[] visited = new boolean[n];
+        Queue<int[]> queue = new LinkedList<>();
+        queue.offer(new int[]{0, 0});
+        visited[0] = true;
+
+        while (!queue.isEmpty()) {
+            int[] curr = queue.poll();
+            int node = curr[0], color = curr[1];
+            nodeColor[node] = color;
+            colorCount[color]++;
+
+            for (int neighbor : graph.get(node)) {
+                if (!visited[neighbor]) {
+                    visited[neighbor] = true;
+                    queue.offer(new int[]{neighbor, 1 - color});
+                }
+            }
+        }
+    }
+}