#3175

Medium

LeetCode Problem Workspace

Find The First Player to win K Games in a Row

Determine which player first wins k consecutive games using array simulation logic to track ongoing victories efficiently.

array simulation

Problem Statement

You are given n players standing in a line, each with a unique skill level represented in an array skills where skills[i] is the skill of player i. Players compete in sequential matches with the player at the front of the queue facing the next player.

In each match, the player with higher skill wins and remains at the front while the loser moves to the back of the queue. Determine the first player to win k consecutive matches using an array plus simulation approach.

Examples

Example 1

Input: skills = [4,2,6,3,9], k = 2

Output: 2

Initially, the queue of players is [0,1,2,3,4] . The following process happens: Player 2 won k = 2 games in a row, so the winner is player 2.

Example 2

Input: skills = [2,5,4], k = 3

Output: 1

Initially, the queue of players is [0,1,2] . The following process happens: Player 1 won k = 3 games in a row, so the winner is player 1.

Constraints

n == skills.length
2 <= n <= 105
1 <= k <= 109
1 <= skills[i] <= 106
All integers in skills are unique.

Solution Approach

Simulate Matches Sequentially

Maintain a queue of player indices and a variable for the current consecutive win count. For each match, compare the front two players, update the winner, increment or reset the streak, and continue until the streak reaches k.

Track Maximum Skill Optimization

If k >= n, the player with the maximum skill will inevitably win k consecutive games. Identify the maximum skill player first to shortcut simulation when k is large relative to n.

Efficient Array Access

Use direct indexing into the skills array rather than removing elements from a queue structure to reduce overhead. Maintain a pointer for the current front player and track streaks efficiently.

Complexity Analysis

Metric	Value
Time	Depends on the final approach
Space	Depends on the final approach

Time complexity is O(n) in the worst case when simulating until a player reaches k wins, since each player is compared at most once per match. Space complexity is O(1) if only counters and indices are used without an explicit queue.

What Interviewers Usually Probe

Are you tracking consecutive wins correctly?
Consider the maximum skill shortcut when k is very large.
Check for off-by-one errors when updating the streak and winner.

Common Pitfalls or Variants

Common pitfalls

Resetting the streak incorrectly when the winner changes.
Failing to handle the case when k >= n efficiently.
Modifying the array instead of using indices, leading to unnecessary overhead.

Follow-up variants

Return the list of players who reach k wins first in multiple simulations.
Compute the number of matches needed for the first player to reach k wins.
Handle ties in skill levels and determine who reaches k wins first under tie rules.

FAQ

What is the main pattern in Find The First Player to win K Games in a Row?

The main pattern is array plus simulation, tracking consecutive wins through sequential array comparisons.

How do I handle large k values efficiently?

When k >= n, identify the maximum skill player first, since they will inevitably win k games in a row without full simulation.

Can I use a queue to simulate matches?

Yes, but it's more efficient to use array indices to track the front player and streak count rather than removing elements from a queue.

What are common mistakes in this problem?

Resetting streaks incorrectly, not handling k >= n efficiently, and modifying the array unnecessarily instead of using indices.

Is there a shortcut to find the winner without simulating all matches?

Yes, if k >= n, the player with the highest skill is guaranteed to win k consecutive games, so simulation can stop early.

terminal

Solution

Solution 1: Quick Thinking

We notice that each time the first two elements of the array are compared, regardless of the result, the next comparison will always be between the next element in the array and the current winner. Therefore, if we have looped $n-1$ times, the final winner must be the maximum element in the array. Otherwise, if an element has won consecutively $k$ times, then this element is the final winner.

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class Solution:
    def findWinningPlayer(self, skills: List[int], k: int) -> int:
        n = len(skills)
        k = min(k, n - 1)
        i = cnt = 0
        for j in range(1, n):
            if skills[i] < skills[j]:
                i = j
                cnt = 1
            else:
                cnt += 1
            if cnt == k:
                break
        return i

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