NashEquilibrium.java

import java.util.Scanner;

public class NashEquilibrium {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    int[][] game = new int[2][2];

    System.out.println("Enter the payoff matrix for Player 1 (separate values with spaces):");
    for (int i = 0; i < 2; i++) {
      for (int j = 0; j < 2; j++) {
        game[i][j] = input.nextInt();
      }
    }

    while (true) {
      System.out.println("Enter Player 2's move (0 or 1):");
      int p2move = input.nextInt();

      int bestP1move = 0;
      if (game[0][p2move] < game[1][p2move]) {
        bestP1move = 1;
      }

      System.out.println("Player 1's best move: " + bestP1move);

      System.out.println("Enter Player 1's move (0 or 1):");
      int p1move = input.nextInt();

      int bestP2move = 0;
      if (game[p1move][0] < game[p1move][1]) {
        bestP2move = 1;
      }

      System.out.println("Player 2's best move: " + bestP2move);

      if (bestP1move == p1move && bestP2move == p2move) {
        System.out.println("Equilibrium reached!");
        break;
      }

      System.out.println("Not yet in equilibrium. Keep playing.");
    }
  }
}