Add all the A tasks

2013-04-10 14:58:50 -07:00 · 2013-04-10 14:58:50 -07:00 · 051504d65b
commit 051504d65b
parent 2dd7375f96
1608 changed files with 18584 additions and 0 deletions
--- a/Task/Atomic-updates/Java/atomic-updates.java
+++ b/Task/Atomic-updates/Java/atomic-updates.java
@ -0,0 +1,119 @@
+import java.util.Arrays;
+import java.util.Random;
+
+public class AtomicUpdates
+{
+  public static class Buckets
+  {
+    private final int[] data;
+
+    public Buckets(int[] data)
+    {
+      this.data = data.clone();
+    }
+
+    public int getBucket(int index)
+    {
+      synchronized (data)
+      {  return data[index];  }
+    }
+
+    public int transfer(int srcBucketIndex, int destBucketIndex, int amount)
+    {
+      if (amount == 0)
+        return 0;
+      // Negative transfers will happen in the opposite direction
+      if (amount < 0)
+      {
+        int tempIndex = srcBucketIndex;
+        srcBucketIndex = destBucketIndex;
+        destBucketIndex = tempIndex;
+        amount = -amount;
+      }
+      synchronized (data)
+      {
+        if (amount > data[srcBucketIndex])
+          amount = data[srcBucketIndex];
+        if (amount <= 0)
+          return 0;
+        data[srcBucketIndex] -= amount;
+        data[destBucketIndex] += amount;
+        return amount;
+      }
+    }
+
+    public int[] getBuckets()
+    {
+      synchronized (data)
+      {  return data.clone();  }
+    }
+  }
+
+  public static int getTotal(int[] values)
+  {
+    int totalValue = 0;
+    for (int i = values.length - 1; i >= 0; i--)
+      totalValue += values[i];
+    return totalValue;
+  }
+
+  public static void main(String[] args)
+  {
+    final int NUM_BUCKETS = 10;
+    Random rnd = new Random();
+    final int[] values = new int[NUM_BUCKETS];
+    for (int i = 0; i < values.length; i++)
+      values[i] = rnd.nextInt(10);
+    System.out.println("Initial Array: " + getTotal(values) + " " + Arrays.toString(values));
+    final Buckets buckets = new Buckets(values);
+
+    new Thread(new Runnable() {
+        public void run()
+        {
+          Random r = new Random();
+          while (true)
+          {
+            int srcBucketIndex = r.nextInt(NUM_BUCKETS);
+            int destBucketIndex = r.nextInt(NUM_BUCKETS);
+            int amount = (buckets.getBucket(srcBucketIndex) - buckets.getBucket(destBucketIndex)) >> 1;
+            if (amount != 0)
+              buckets.transfer(srcBucketIndex, destBucketIndex, amount);
+          }
+        }
+      }
+    ).start();
+
+    new Thread(new Runnable() {
+        public void run()
+        {
+          Random r = new Random();
+          while (true)
+          {
+            int srcBucketIndex = r.nextInt(NUM_BUCKETS);
+            int destBucketIndex = r.nextInt(NUM_BUCKETS);
+            int srcBucketAmount = buckets.getBucket(srcBucketIndex);
+            int destBucketAmount = buckets.getBucket(destBucketIndex);
+            int amount = r.nextInt(srcBucketAmount + destBucketAmount + 1) - destBucketAmount;
+            if (amount != 0)
+              buckets.transfer(srcBucketIndex, destBucketIndex, amount);
+          }
+        }
+      }
+    ).start();
+
+    while (true)
+    {
+      long nextPrintTime = System.currentTimeMillis() + 3000;
+      long curTime;
+      while ((curTime = System.currentTimeMillis()) < nextPrintTime)
+      {
+        try
+        {  Thread.sleep(nextPrintTime - curTime);  }
+        catch (InterruptedException e)
+        {  }
+      }
+      int[] bucketValues = buckets.getBuckets();
+      System.out.println("Current values: " + getTotal(bucketValues) + " " + Arrays.toString(bucketValues));
+    }
+  }
+}