#2374

Node With Highest Edge Score

Medium
Hash TableGraph TheoryHash MapArray
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Approaches

Brute ForceOptimal
Complexity Comparison
Brute ForceOptimal Solution
Time
O(n²)
O(n)
Space
O(1)
O(n)
💡

Intuition

Time O(n)Space O(n)

In the optimal approach, we use a single pass to calculate the edge scores by leveraging the fact that each node has exactly one outgoing edge. This allows us to efficiently compute scores in O(n) time.

⚙️

Algorithm

3 steps
  1. 1Step 1: Initialize an array `score` of size n with all zeros to store the edge scores for each node.
  2. 2Step 2: Iterate through the `edges` array. For each index `i`, add `i` to `score[edges[i]]` since `edges[i]` is the node that `i` points to.
  3. 3Step 3: After populating the scores, iterate through the `score` array to find the node with the maximum score, ensuring to return the smallest index in case of ties.
solution.py14 lines
1# Full working Python code
2
3def highestEdgeScore(edges):
4    n = len(edges)
5    score = [0] * n
6    for i in range(n):
7        score[edges[i]] += i
8    max_score = -1
9    result_node = -1
10    for i in range(n):
11        if score[i] > max_score or (score[i] == max_score and i < result_node):
12            max_score = score[i]
13            result_node = i
14    return result_node

Complexity note: The time complexity is O(n) because we make a single pass through the edges to calculate scores and another pass to find the maximum. The space complexity is O(n) due to the score array used to store edge scores.

  • 1Each node has exactly one outgoing edge, simplifying the score calculation.
  • 2The edge score is cumulative based on the indices of nodes pointing to it.

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