Data commit

Task/24-game/Java/24-game.java

@@ -0,0 +1,62 @@
+import java.util.*;
+
+public class Game24 {
+    static Random r = new Random();
+
+    public static void main(String[] args) {
+
+        int[] digits = randomDigits();
+        Scanner in = new Scanner(System.in);
+
+        System.out.print("Make 24 using these digits: ");
+        System.out.println(Arrays.toString(digits));
+        System.out.print("> ");
+
+        Stack<Float> s = new Stack<>();
+        long total = 0;
+        for (char c : in.nextLine().toCharArray()) {
+            if ('0' <= c && c <= '9') {
+                int d = c - '0';
+                total += (1 << (d * 5));
+                s.push((float) d);
+            } else if ("+/-*".indexOf(c) != -1) {
+                s.push(applyOperator(s.pop(), s.pop(), c));
+            }
+        }
+        if (tallyDigits(digits) != total)
+            System.out.print("Not the same digits. ");
+        else if (Math.abs(24 - s.peek()) < 0.001F)
+            System.out.println("Correct!");
+        else
+            System.out.print("Not correct.");
+    }
+
+    static float applyOperator(float a, float b, char c) {
+        switch (c) {
+            case '+':
+                return a + b;
+            case '-':
+                return b - a;
+            case '*':
+                return a * b;
+            case '/':
+                return b / a;
+            default:
+                return Float.NaN;
+        }
+    }
+
+    static long tallyDigits(int[] a) {
+        long total = 0;
+        for (int i = 0; i < 4; i++)
+            total += (1 << (a[i] * 5));
+        return total;
+    }
+
+    static int[] randomDigits() {
+        int[] result = new int[4];
+        for (int i = 0; i < 4; i++)
+            result[i] = r.nextInt(9) + 1;
+        return result;
+    }
+}