Introduction

In this blog post, we will explore how to solve the LeetCode problem "2374" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

You are given a directed graph with n nodes labeled from 0 to n - 1, where each node has exactly one outgoing edge. The graph is represented by a given 0-indexed integer array edges of length n, where edges[i] indicates that there is a directed edge from node i to node edges[i]. The edge score of a node i is defined as the sum of the labels of all the nodes that have an edge pointing to i. Return the node with the highest edge score. If multiple nodes have the same edge score, return the node with the smallest index. Example 1: Input: edges = [1,0,0,0,0,7,7,5] Output: 7 Explanation: - The nodes 1, 2, 3 and 4 have an edge pointing to node 0. The edge score of node 0 is 1 + 2 + 3 + 4 = 10. - The node 0 has an edge pointing to node 1. The edge score of node 1 is 0. - The node 7 has an edge pointing to node 5. The edge score of node 5 is 7. - The nodes 5 and 6 have an edge pointing to node 7. The edge score of node 7 is 5 + 6 = 11. Node 7 has the highest edge score so return 7. Example 2: Input: edges = [2,0,0,2] Output: 0 Explanation: - The nodes 1 and 2 have an edge pointing to node 0. The edge score of node 0 is 1 + 2 = 3. - The nodes 0 and 3 have an edge pointing to node 2. The edge score of node 2 is 0 + 3 = 3. Nodes 0 and 2 both have an edge score of 3. Since node 0 has a smaller index, we return 0. Constraints: n == edges.length 2 <= n <= 105 0 <= edges[i] < n edges[i] != i

Explanation

• Calculate Edge Scores: Iterate through the edges array and for each node, determine which nodes point to it. Sum the labels of these nodes to compute the edge score for each node.
  • Find Maximum Score: Iterate through the calculated edge scores to find the maximum score.
  • Handle Ties: If multiple nodes have the same maximum edge score, return the node with the smallest index.

• Runtime Complexity: O(n), where n is the number of nodes. Storage Complexity: O(n)

Code

    def edge_score(edges):
    """
    Finds the node with the highest edge score in a directed graph.

    Args:
        edges: A list of integers representing the edges of the graph.

    Returns:
        The index of the node with the highest edge score.
    """

    n = len(edges)
    scores = [0] * n

    for i, target in enumerate(edges):
        scores[target] += i

    max_score = -1
    best_node = -1

    for i, score in enumerate(scores):
        if score > max_score:
            max_score = score
            best_node = i
        elif score == max_score and i < best_node:
            best_node = i

    return best_node