May 30

Author: siddydutta

2025-05-May-LeetCoding-Challenge/Find Closest Node to Given Two Nodes.py

@@ -0,0 +1,46 @@
+class Solution:
+    def __init__(self):
+        self.edges = []
+
+    def __compute_distances(self, start: int) -> list[int]:
+        distances = [-1] * len(self.edges)
+        last_node = [(start, 0)]  # every node has at-most one outgoing edge
+        visited = set()
+        while last_node:
+            node, distance = last_node.pop()
+            if node in visited:
+                continue
+            distances[node] = distance
+            visited.add(node)
+            if self.edges[node] != -1:
+                last_node.append((self.edges[node], distance + 1))
+        return distances
+
+    def closestMeetingNode(self, edges: list[int], node1: int, node2: int) -> int:
+        self.edges = edges
+        distances1, distances2 = map(self.__compute_distances, (node1, node2))
+        min_idx, max_min_dist = -1, float('inf')
+        for idx, (d1, d2) in enumerate(zip(distances1, distances2)):
+            if d1 == -1 or d2 == -1:
+                continue
+            curr_max = max(d1, d2)
+            if curr_max < max_min_dist:
+                min_idx = idx
+                max_min_dist = curr_max
+        return min_idx
+
+
+def main():
+    edges = [2, 2, 3, -1]
+    node1 = 0
+    node2 = 1
+    assert Solution().closestMeetingNode(edges, node1, node2) == 2
+
+    edges = [1, 2, -1]
+    node1 = 0
+    node2 = 2
+    assert Solution().closestMeetingNode(edges, node1, node2) == 2
+
+
+if __name__ == '__main__':
+    main()

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

@@ -33,13 +33,13 @@
 | May 27 | [2894. Divisible and Non-divisible Sums Difference](https://leetcode.com/problems/divisible-and-non-divisible-sums-difference/) | Easy | Solved |
 | May 28 | []() |  |  |
 | May 29 | []() |  |  |
-| May 30 | []() |  |  |
+| 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 | []() |  |  |
 
 
 ## Summary
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 7 | 7 | 0 |
-| Medium | 13 | 10 | 3 |
+| Medium | 14 | 11 | 3 |
 | Hard   | 6 | 1 | 5 |