排序算法问题,使用Java;得到错误的结果。

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英文:

sorting algorithm problem in Java; get wrong results

问题

public class MainProgram {

    public static void main(String[] args) {

        int[] array = {3, 1, 5, 99, 3, 12};

        System.out.println(MainProgram.indexOfSmallestFrom(array, 0));
        System.out.println(MainProgram.indexOfSmallestFrom(array, 1));
        System.out.println(MainProgram.indexOfSmallestFrom(array, 2));
    }

    public static int indexOfSmallestFrom(int[] table, int startIndex){
        int count = startIndex;
        int indexOf = 0;
        int smallest = table[startIndex];
        for(int i = startIndex; i < table.length; i++){
            if(smallest > table[i]){
               smallest = table[i];
               count++;
            }
              indexOf = count; 
        }
            return indexOf;
    }   
}
英文:

Create in the class MainProgram a class method called indexOfSmallestFrom. It works similarly to the method in the previous section, but only considers the table values from a certain index forwards. In addition to the table, it receives this start index as a parameter.

In this example the first method call searches for the index of the smallest number, starting from index 0. Starting from index 0, the smallest number is -1 and its index is 0. The second method call searches for the index of the smallest value starting from index 1. In this case the smallest number is 6 and its index is 1. The third calls searches for the index of the smallest value starting at index 2. Then the smallest number is 8 and its index is 3.

the index should be printed for the smallest array.
According to the int array, my output should be:

1
1
4

but i get:

1
1
3

can't figure out logically, why.

public class MainProgram {

    public static void main(String[] args) {

        int[] array = {3, 1, 5, 99, 3, 12};
        
        System.out.println(MainProgram.indexOfSmallestFrom(array, 0));
        System.out.println(MainProgram.indexOfSmallestFrom(array, 1));
        System.out.println(MainProgram.indexOfSmallestFrom(array, 2));
    }
    
    public static int indexOfSmallestFrom(int[] table, int startIndex){
        int count = startIndex;
        int indexOf = 0;
        int smallest = table[startIndex];
        for(int i = startIndex; i &lt; table.length; i++){
            if(smallest &gt; table[i]){
               smallest = table[i];
               count++;
            }
              indexOf = count; 
        }
            return indexOf;
    }   
 
}

答案1

得分: -1

只有在找到一个比初始的indexOf位置的值小的元素时,更新indexOf。

在遍历所有值后... 返回最终更新的indexOf。

    // "static void main"必须在公共类中定义。
    public class Main {
        public static void main(String[] args) {

            int[] array = {3, 1, 5, 99, 3, 12};

            System.out.println(indexOfSmallestFrom(array, 0));
            System.out.println(indexOfSmallestFrom(array, 1));
            System.out.println(indexOfSmallestFrom(array, 2));
        }

        public static int indexOfSmallestFrom(int[] table, int startIndex){
            int indexOf = startIndex;
            int smallest = table[startIndex];
            for(int i = startIndex; i < table.length; i++){
                if(smallest > table[i]){
                   smallest = table[i];
                   indexOf = i;
                }
            }
                return indexOf;
        }   
    }
英文:

Just update indexOf when you find an element smaller than the value at the indexOf which is initially initialized as startIndex.

After iterating through all the values... return the finally updated indexOf.

// &quot;static void main&quot; must be defined in a public class.
public class Main {
    public static void main(String[] args) {

        int[] array = {3, 1, 5, 99, 3, 12};

        System.out.println(indexOfSmallestFrom(array, 0));
        System.out.println(indexOfSmallestFrom(array, 1));
        System.out.println(indexOfSmallestFrom(array, 2));
    }

    public static int indexOfSmallestFrom(int[] table, int startIndex){
        int indexOf = startIndex;
        int smallest = table[startIndex];
        for(int i = startIndex; i &lt; table.length; i++){
            if(smallest &gt; table[i]){
               smallest = table[i];
               indexOf = i;
            }
        }
            return indexOf;
    }   
}

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  • 本文由 发表于 2020年8月26日 00:48:50
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