May 28

Author: siddydutta

2025-05-May-LeetCoding-Challenge/Maximize the Number of Target Nodes After Connecting Trees I.py

@@ -0,0 +1,54 @@
+from collections import deque
+
+
+class Solution:
+    def __build_adj_list(self, edges: list[list[int]]) -> list[list[int]]:
+        n = len(edges) + 1
+        graph = [[] for _ in range(n)]
+        for u, v in edges:
+            graph[u].append(v)
+            graph[v].append(u)
+        return graph
+
+    def __bfs(self, graph: list[list[int]], start: int, k: int) -> int:
+        level = 0
+        queue = deque([start])
+        visited = {start}
+        count = 1  # node is always target to itself
+        while queue and level < k:
+            for _ in range(len(queue)):
+                node = queue.popleft()
+                for neighbour in graph[node]:
+                    if neighbour not in visited:
+                        count += 1
+                        visited.add(neighbour)
+                        queue.append(neighbour)
+            level += 1
+        return count
+
+    def maxTargetNodes(
+        self, edges1: list[list[int]], edges2: list[list[int]], k: int
+    ) -> list[int]:
+        graph1, graph2 = map(self.__build_adj_list, (edges1, edges2))
+        n_targets1 = [self.__bfs(graph1, node, k) for node in range(len(graph1))]
+        max_targets2 = 0
+        if k > 0:
+            for node in range(len(graph2)):
+                max_targets2 = max(max_targets2, self.__bfs(graph2, node, k - 1))
+        return [n_targets + max_targets2 for n_targets in n_targets1]
+
+
+def main():
+    edges1 = [[0, 1], [0, 2], [2, 3], [2, 4]]
+    edges2 = [[0, 1], [0, 2], [0, 3], [2, 7], [1, 4], [4, 5], [4, 6]]
+    k = 2
+    assert Solution().maxTargetNodes(edges1, edges2, k) == [9, 7, 9, 8, 8]
+
+    edges1 = [[0, 1], [0, 2], [0, 3], [0, 4]]
+    edges2 = [[0, 1], [1, 2], [2, 3]]
+    k = 1
+    assert Solution().maxTargetNodes(edges1, edges2, k) == [6, 3, 3, 3, 3]
+
+
+if __name__ == '__main__':
+    main()

2025-05-May-LeetCoding-Challenge/README.md

@@ -31,7 +31,7 @@
 | May 25 | [2131. Longest Palindrome by Concatenating Two Letter Words](https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/) | Medium | Solved |
 | May 26 | [1857. Largest Color Value in a Directed Graph](https://leetcode.com/problems/largest-color-value-in-a-directed-graph/) | Hard | Unsolved |
 | May 27 | [2894. Divisible and Non-divisible Sums Difference](https://leetcode.com/problems/divisible-and-non-divisible-sums-difference/) | Easy | Solved |
-| May 28 | []() |  |  |
+| May 28 | [3372. Maximize the Number of Target Nodes After Connecting Trees I](https://leetcode.com/problems/maximize-the-number-of-target-nodes-after-connecting-trees-i/) | Medium | Solved |
 | May 29 | []() |  |  |
 | May 30 | [2359. Find Closest Node to Given Two Nodes](https://leetcode.com/problems/find-closest-node-to-given-two-nodes/) | Medium | Solved |
 | May 31 | []() |  |  |
@@ -41,5 +41,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 7 | 7 | 0 |
-| Medium | 14 | 11 | 3 |
+| Medium | 15 | 12 | 3 |
 | Hard   | 6 | 1 | 5 |