cpp-flashcards/org/study_deck_02/dsa/graphs/2924-find-champion-ii.org

• 2924. Find Champion II
  • Approach
  • Python
  • C++

TODO 2924. Find Champion II   medium

There are n teams numbered from 0 to n - 1 in a tournament; each team is also a node in a DAG.

You are given the integer n and a 0-indexed 2D integer array edges of length m representing the DAG, where edges[i] = [u_{i}, v_{i}] indicates that there is a directed edge from team u_{i} to team v_{i} in the graph.

A directed edge from a to b in the graph means that team a is stronger than team b and team b is weaker than team a.

Team a will be the champion of the tournament if there is no team b that is stronger than team a.

Return the team that will be the champion of the tournament if there is a unique champion, otherwise, return /~-1~./

Notes

• A cycle is a series of nodes a_{1}, a_{2}, ..., a_{n}, a_{n+1} such that node a_{1} is the same node as node a_{n+1}, the nodes a_{1}, a_{2}, ..., a_{n} are distinct, and there is a directed edge from the node a_{i} to node a_{i+1} for every i in the range [1, n].
• A DAG is a directed graph that does not have any cycle.

Example 1:

Input: n = 3, edges = [[0,1],[1,2]]
Output: 0
Explanation: Team 1 is weaker than team 0. Team 2 is weaker than team 1. So the champion is team 0.

Example 2:

Input: n = 4, edges = [[0,2],[1,3],[1,2]]
Output: -1
Explanation: Team 2 is weaker than team 0 and team 1. Team 3 is weaker than team 1. But team 1 and team 0 are not weaker than any other teams. So the answer is -1.

Constraints:

• 1 <= n <= 100
• m == edges.length
• 0 <= m <= n * (n - 1) / 2
• edges[i].length == 2
• 0 <= edge[i][j] <= n - 1
• edges[i][0] != edges[i][1]
• The input is generated such that if team a is stronger than team b, team b is not stronger than team a.
• The input is generated such that if team a is stronger than team b and team b is stronger than team c, then team a is stronger than team c.

TODO Approach

Write your approach here.

TODO Python

class Solution:
    def findChampion(self, n: int, edges: List[List[int]]) -> int:

TODO C++

class Solution {
public:
    int findChampion(int n, vector<vector<int>>& edges) {
        
    }
};