Distinct Element Elimination Algorithm

This project implements an interactive approach to finding the number of Unique Elements in an integer array. Instead of using standard sorting or hashing sets, it employs an Elimination Game mechanic using a Sentinel Value.

⚙️ Algorithm Logic

The system holds a dataset $S$. The user provides inputs to "clear" the board.

1. Initialization: The array is populated with mixed integers (duplicates included).
2. Sentinel Value: We use -1 as a mask to represent "deleted" or "processed" items.
3. Process Loop:
   • User inputs a number $x$.
   • The algorithm scans the array.
   • IF $x$ is found:
     • All instances of $x$ are replaced with -1.
     • The Distinct Counter is incremented by 1.
   • ELSE: No action is taken (input ignored).
4. Termination: The loop breaks when the entire array consists of -1s.

Visual State Transition

Initial: [1, 6, 5, 2, 1, 4, 2]

• User Input: 1
• Action: Mask all 1s. Increment count. State 1: [-1, 6, 5, 2, -1, 4, 2]
• User Input: 2
• Action: Mask all 2s. Increment count. State 2: [-1, 6, 5, -1, -1, 4, -1]

🚀 Usage

1. Compile the code:

   gcc main.c -o elimination_counter

2. Run the executable:

   ./elimination_counter

3. Guess numbers until the program terminates and reports the count of unique numbers.

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This repository demonstrates array modification and interactive state checking in C.