利用hadoop中的map-reduce框架实现了apriori算法。
谁能指导我如何优化apriori算法（在hadoop map reduce中）？
我会非常感激的。
谢谢！
编辑代码：

//MAPPER 
public void map(LongWritable key, Text value, Context context)
        throws IOException, InterruptedException {
    Utils.count++;
    String line = value.toString();
    String[] items = line.split(" ");

    Arrays.sort( items );
    LinkedHashSet myPowerSet = powerset(items);
    for (Iterator iterator = myPowerSet.iterator(); iterator.hasNext();) {
        Object i = iterator.next();
        String _key = i.toString().replaceAll("\\[|\\]| +", "");
        context.write(new Text(_key), new IntWritable(1));
    }
}
//COMBINER
public void reduce(Text key, Iterable<IntWritable> values, Context context)
        throws IOException, InterruptedException {

    int localSum = 0;

    for (IntWritable value : values) {
        localSum += value.get();
    }
    context.write(key, new IntWritable(localSum));
}
//REDUCER
public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException
{
    int minSupportCount = 3;
    int supportCount = 0;

    for(IntWritable value : values) {
        supportCount += value.get();
    }
    if (supportCount >= minSupportCount) {
        context.write(key, new IntWritable(supportCount));  
    }
}