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3434. Find the Number of Distinct Colors Among the Balls

My accepted Python solution to LeetCode problem 3434, Find the Number of Distinct Colors Among the Balls, running in 59ms.

  • Difficulty: Medium
  • Python
  • Runtime 59ms
  • Memory 64.1MB

Read the problem on LeetCode View on GitHub

The problem statement is LeetCode’s and stays on their site. What follows is my accepted solution.

Python

Accepted on LeetCode — runtime 59ms, memory 64.1MB, accepted 2026-01-02.

python
class Solution:
    def queryResults(self, limit: int, queries: List[List[int]]) -> List[int]:
        ball_to_color = {}  # ball -> color
        color_count = {}    # color -> count of balls with this color
        
        result = []
        
        for ball, color in queries:
            # If ball already has a color, decrease that color's count
            if ball in ball_to_color:
                old_color = ball_to_color[ball]
                color_count[old_color] -= 1
                if color_count[old_color] == 0:
                    del color_count[old_color]
            
            # Assign new color to ball
            ball_to_color[ball] = color
            color_count[color] = color_count.get(color, 0) + 1
            
            # Count distinct colors
            result.append(len(color_count))
        
        return result

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