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所以我有一门课程应该接受一个数字并获得主要因素。然后将这些因子存储在 ArrayList、Factors 中，并在最后打印出来。问题是它只适用于 4，当我做 16 时它会冻结。任何帮助都会很棒！

我的java类：

package com.frostbytedev.addsub;

import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.util.ArrayList;

/**
 * Created by Steven on 7/4/13.
 */
public class Factor extends Activity implements View.OnClickListener{
    ArrayList<Integer> Factors = new ArrayList<Integer>();
    ArrayList<Integer> toAdd = new ArrayList<Integer>();
    ArrayList<Integer> toRemove = new ArrayList<Integer>();
    int numToFactor;
    TextView FactorResults;
    EditText NumberInput;
    Button bFactor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.factor);
        initialize();

    }

    private void initialize() {
        FactorResults = (TextView)findViewById(R.id.tvFactors);
        NumberInput = (EditText)findViewById(R.id.etNumber);
        bFactor = (Button)findViewById(R.id.bFactor);
        bFactor.setOnClickListener(this);
    }
    @Override
    public void onClick(View view) {
        switch(view.getId()){
            case R.id.bFactor:
                numToFactor = Integer.parseInt(NumberInput.getText().toString());
                FactorNumber(numToFactor);
                FindFactors(Factors);
                PrintFactors(Factors);
        }
    }

    private void PrintFactors(ArrayList<Integer> factors) {
        //String joined = Factors.get(0)+", "+Factors.get(1);
        String joined = TextUtils.join(", ", Factors);
        FactorResults.setText(joined);
    }

    private void FactorNumber(int number) {
        int multipliedFactors=1;
        int i;
        double middle = Math.ceil(number/2);
        FactorResults.setText(String.valueOf(middle));
        for(i=(int)middle;i>1;i--){
            if(number%i==0){
                Factors.add(i);
            }
            else
                return;
        }
            for(i=0;i<Factors.size();i++){
                multipliedFactors*=Factors.get(i);
            }
        if(multipliedFactors<number){
            FactorNumber(number);
        }
        if(Factors.size()==0){
            FactorResults.setText(number+" has no factors!");
        }
    }
        public void FindFactors(ArrayList<Integer> factors){
        int i;
            for(i=0;i<factors.size();i++){
                int y;
                double middle;
                middle = Math.ceil(factors.get(i)/2);
                for(y=(int)middle;y>1;y--){
                    if(i%y==0){
                        toAdd.add(y);
                        toAdd.add(factors.get(i)/y);
                        toRemove.add(i);
                        RemoveExtras(toRemove);
                        AddNewFactors(toAdd);
                    FindFactors(Factors);
                    }
                    else
                        return;
                }

                }

            }


    private void AddNewFactors(ArrayList<Integer> toAdd) {
        int i;
        for(i=0;i<toAdd.size();i++){
            Factors.add(toAdd.get(i));
        }
    }

    private void RemoveExtras(ArrayList<Integer> toRemove) {
        int i;
        for(i=0;i<toRemove.size();i++){
            Factors.remove(toRemove.get(i));
        }
    }
}
4

1 回答 1

1

试试这个算法

private void factorNumber(int n) {
    for (int i = 2; i <= n / i; i++) {
      while (n % i == 0) {
        factors.add(i);
        n /= i;
      }
    }
    if (n > 1) {
      factors.add(n);
    }
}
于 2013-07-05T15:42:34.770 回答