Minimum matches in a single-elimination tournament with byes: An elimination tournament has 139 players. Some rounds may include a bye if there is an odd number. What is the minimum number of matches required to determine a single champion?

Difficulty: Easy

Correct Answer: 138

Explanation:


Introduction / Context:
In any single-elimination tournament (knockout), each match eliminates exactly one player. Regardless of how byes are assigned, to go from n players down to 1 champion, we must eliminate n − 1 players, which requires n − 1 matches.


Given Data / Assumptions:

  • n = 139 entrants.
  • Single-elimination; a bye is not a match and eliminates no one.
  • Each match eliminates exactly one player.


Concept / Approach:

  • Matches needed = total eliminations = n − 1.


Step-by-Step Solution:

Required matches = 139 − 1 = 138


Verification / Alternative check:
Construct any bracket: every non-champion loses exactly one match; count of losses equals number of matches. The champion has no loss. Thus total matches equals losers = 138.


Why Other Options Are Wrong:

  • 136, 137 undercount; 139 overcounts by one.


Common Pitfalls:

  • Thinking byes change the total count; they alter scheduling, not the total eliminations.


Final Answer:
138

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