java - 避免在java中嵌套foreach循环

Question

自从我参加编码类(class)以来，已经有大约 20 年了。我有时会为了好玩而重新拿起它，但我的代码很笨重且效率低下。

我有一个只有 400 多个元素的数组。我目前已经在该数组上运行了嵌套的 foreach 循环。

import acm.program.ConsoleProgram;
import java.awt.Color;
import acm.io.IODialog;
import java.text.*;
import static java.lang.Math.*;
import java.util.*;

/** Tests to see if user color matches sample colors */

public class test extends ConsoleProgram

{

   //defining sample colors

   Color[] dmc =
   {
      new Color(255,255,255),
      new Color(148,91,128),
      new Color(206,148,186),
      new Color(236,207,225),
      new Color(243,218,228),

   };

 public void run()
 {
    average();

 }

 //averages three colors, then tests for match to given color

 public void average()
 {

    //asks for user color
    IODialog dialog = new IODialog();
    int stitchRed= dialog.readInt("Enter red value: ");
    int stitchGreen= dialog.readInt("Enter green value: ");
    int stitchBlue= dialog.readInt("Enter blue value: ");
    Color stitchColor= new Color(stitchRed,stitchGreen,stitchBlue);

    //gets averages for dmc colors
    for (Color i:dmc)
    {
       for (Color j:dmc)
       {
          for (Color k:dmc)
          {
              int indexI = Arrays.asList(dmc).indexOf(i);
              int indexJ = Arrays.asList(dmc).indexOf(j);
              int indexK = Arrays.asList(dmc).indexOf(k);
              if(indexI <= indexJ && indexJ <= indexK)
              {
                 int iRed = i.getRed();
                 int jRed = j.getRed();
                 int kRed = k.getRed();
                 int iGreen = i.getGreen();
                 int jGreen = j.getGreen();
                 int kGreen = k.getGreen();
                 int iBlue = i.getBlue();
                 int jBlue = j.getBlue();
                 int kBlue = k.getBlue();
                 int redAverage = (iRed+jRed+kRed)/3;
                 int greenAverage = (iGreen+jGreen+kGreen)/3;
                 int blueAverage = (iBlue+jBlue+kBlue)/3;
                 Color colorAverage = new Color(redAverage,greenAverage,blueAverage);

                 //tests to see if any thread average equals user color
                 if (colorAverage.equals(stitchColor))
                 {
                    println("The color match is: " + i + ", " + j + ", " + k);
                 }
            }
         }
       }
     }

     println("no more matches");
   }
 }

编译得很好，但运行速度非常慢。

有没有更有效的方法来做到这一点？
可能是一种绕过嵌套的方法 - 其效果是:

for(颜色 i,j,k:dmc)

？

Answer 1

它等于@C0der的答案，只是对问题的变量使用相同的名称。

    for (int indexI = 0; indexI < dmc.length; indexI++) {
        Color i = dmc[indexI];
        for (int indexJ = indexI; indexJ< dmc.length; indexJ++) {
            Color j = dmc[indexJ];
            for (int indexK = indexJ; indexK< dmc.length; indexK++) {
                Color k = dmc[indexK];
                //....
            }
        }
    }

编辑:

public void average() {
    //asks for user color
    IODialog dialog = new IODialog();
    int stitchRed = dialog.readInt("Enter red value: ");
    int stitchGreen = dialog.readInt("Enter green value: ");
    int stitchBlue = dialog.readInt("Enter blue value: ");
    Color stitchColor = new Color(stitchRed, stitchGreen, stitchBlue);
    for (int indexI = 0; indexI < dmc.length; indexI++) {
        Color i = dmc[indexI];
        for (int indexJ = indexI; indexJ < dmc.length; indexJ++) {
            Color j = dmc[indexJ];
            for (int indexK = indexJ; indexK < dmc.length; indexK++) {
                Color k = dmc[indexK];
                int iRed = i.getRed();
                int jRed = j.getRed();
                int kRed = k.getRed();
                int iGreen = i.getGreen();
                int jGreen = j.getGreen();
                int kGreen = k.getGreen();
                int iBlue = i.getBlue();
                int jBlue = j.getBlue();
                int kBlue = k.getBlue();
                int redAverage = (iRed + jRed + kRed) / 3;
                int greenAverage = (iGreen + jGreen + kGreen) / 3;
                int blueAverage = (iBlue + jBlue + kBlue) / 3;
                Color colorAverage = new Color(redAverage, greenAverage, blueAverage);
                //tests to see if any thread average equals user color
                if (colorAverage.equals(stitchColor)) {
                    System.out.println("The color match is: " + i + ", " + j + ", " + k);
                }
            }
        }
    }

    System.out.println("no more matches");
}