在两个整数数组中找到共同的元素 [英] finding common elements in two integer arrays java

问题描述

代码多次返回0和公用数字。我希望它一次返回具有公共数字的数组！因此，如何返回两个数组都通用的数组。我想返回{2,7,4}-像这样。当我尝试返回数组时，我总是越界异常。
谢谢，
巴里

The code returns 0 and the common numbers more than once. I want it to return an array with the common numbers once! So how do I return an array with numbers that are common to both arrays. I want to return {2,7,4} - something like this. I keep getting out of bounds exceptions when I try to return an array. Thanks, Barry

public class Test {
    public int findCommonElement(int[] a, int[] b){
        int counter=0;
        int temp= 0;
        int tempCounter = 0;
        for(int i=0; i<a.length; i++){
            temp=a[i];
            tempCounter=0;
            for(int j=0; j<b.length; j++){
                if (temp==b[j]){
                    tempCounter++;  
                }

            }

            if (tempCounter == 1) {
                temp = a[i];

                counter++;

                System.out.println(temp);

            }

        }

        return 0;
    }

    public static void main(String []args){
        int myArray[] = {2,2,7,7,2,1,5,4,5,1,1};
        int myArray2[] = {2,3,4,7,10};


        Test hello = new Test ();
        System.out.println(hello.findCommonElement(myArray, myArray2));

    }
}

推荐答案

基本上，两个元素中公共元素的数量是动态的。因此，如果您尝试将公共元素放入数组中，则将无法进行，因为您需要声明此数组的大小（在这种情况下将是动态的）。

Basically the number of common element from the two elements will be dynamic. Hence if you try to put common elements into an array then it won't be possible as you need to declare size of this array (which in this case will be dynamic).

考虑使用清单。我试图使逻辑以及全面的变量名尽可能简单。

Consider using list. I've tried to keep the logic as simple as possible along with comprehensive variable names.

    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.List;

    public class Test {

    public static void main(String[] args) {

        int myArray[] = { 2, 2, 7, 7, 2, 1, 5, 4, 5, 1, 1 };
        int myArray2[] = { 2, 3, 4, 7, 10 };

        Test hello = new Test();
        System.out.println(hello.findCommonElement(myArray, myArray2));
    }
    /**
     * 
     * @param a
     * @param b
     * @return commonElements
     */
    public List<Integer> findCommonElement(int[] a, int[] b) {

        List<Integer> commonElements = new ArrayList<Integer>();

        for(int i = 0; i < a.length ;i++) {
            for(int j = 0; j< b.length ; j++) {
                    if(a[i] == b[j]) {  
                    //Check if the list already contains the common element
                        if(!commonElements.contains(a[i])) {
                            //add the common element into the list
                            commonElements.add(a[i]);
                        }
                    }
            }
        }
        return commonElements;
    }
}

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