归并在java中并在、java

2023-09-10 23:05:09 作者:ご浅梦つ

我是新来的Java,并试图用Java来实现归并。然而,即使在运行,而不是期望的有序输出方案几次后,我正在给定的输入与输出相同的用户。我会感激,如果有人可以帮助我了解这个意外的行为。

 进口java.io. *;
进口java.util.Arrays中;


公共类归并{

    公共静态无效的主要(字串[] args)抛出IOException异常{
        BufferedReader中R =新的BufferedReader(新的InputStreamReader(System.in));
        INT ARRAYSIZE =的Integer.parseInt(R.readLine());
        INT [] inputArray =新INT [ARRAYSIZE]
        的for(int i = 0; I< ARRAYSIZE;我++){
            inputArray [I] =的Integer.parseInt(R.readLine());
        }
        归并(inputArray);

        对于(INT J = 0; J< inputArray.length; J ++){
            的System.out.println(inputArray [J]);
        }

    }

    静态无效归并(INT [] A){
        如果(则为a.length→1){
            INT Q =则为a.length / 2;
            INT [] leftArray = Arrays.copyOfRange(A,O,Q);
            INT [] rightArray = Arrays.copyOfRange(A,Q + 1,则为a.length);
            归并(leftArray);
            归并(rightArray);
            A =合并(leftArray,rightArray);
        }
    }

    静态INT []合并(INT [] L,INT [] R){
        INT totElem = l.length + r.length;
        INT [] A =新的INT [totElem]
        INT I,李里;
        I =李= RI = 0;
        而(I< totElem){
            如果((LI< l.length)及及(RI< r.length)){
                如果(L [李]< R [RI]){
                    A [1] = L [李]
                    我++;
                    李++;
                }
                其他 {
                    A [1] = R [RI]
                    我++;
                    RI ++;
                }
            }
            其他 {
                如果(LI> = l.length){
                    而(RI< r.length){
                        A [1] = R [RI]
                        我++;
                        RI ++;
                    }
                }
                如果(RI> = r.length){
                    而(LI< l.length){
                        A [1] = L [李]
                        李++;
                        我++;
                    }
                }
            }
        }
        返回;

    }

}
 

解决方案

下面是你的code修正版本:

 进口java.io. *;
进口java.util.Arrays中;


公共类归并{

    公共静态无效的主要(字串[] args)抛出IOException异常{
        BufferedReader中R =新的BufferedReader(新的InputStreamReader(System.in));
        INT ARRAYSIZE =的Integer.parseInt(R.readLine());
        INT [] inputArray =新INT [ARRAYSIZE]
        的for(int i = 0; I< ARRAYSIZE;我++){
            inputArray [I] =的Integer.parseInt(R.readLine());
        }
        归并(inputArray);

        对于(INT J = 0; J< inputArray.length; J ++){
            的System.out.println(inputArray [J]);
        }

    }

    静态无效归并(INT [] A){
        如果(则为a.length→1){
            INT Q =则为a.length / 2;

            INT [] leftArray = Arrays.copyOfRange(A,O,Q);
            INT [] rightArray = Arrays.copyOfRange(A,Q,则为a.length);

            归并(leftArray);
            归并(rightArray);

            合并(A,leftArray,rightArray);
        }
    }

    静态无效的合并(INT []一,INT [] L,INT [] R){
        INT totElem = l.length + r.length;
        // INT [] A =新的INT [totElem]
        INT I,李里;
        I =李= RI = 0;
        而(I< totElem){
            如果((LI< l.length)及及(RI< r.length)){
                如果(L [李]< R [RI]){
                    A [1] = L [李]
                    我++;
                    李++;
                }
                其他 {
                    A [1] = R [RI]
                    我++;
                    RI ++;
                }
            }
            其他 {
                如果(LI> = l.length){
                    而(RI< r.length){
                        A [1] = R [RI]
                        我++;
                        RI ++;
                    }
                }
                如果(RI> = r.length){
                    而(LI< l.length){
                        A [1] = L [李]
                        李++;
                        我++;
                    }
                }
            }
        }
        //返回;

    }

}
 
做前端好还是Java好 看这三方面

I am new to Java and have tried to implement mergesort in Java. However, even after running the program several times, instead of the desired sorted output, I am getting the same user given input as the output. I would be thankful if someone could help me understand this unexpected behaviour.

import java.io.*;
import java.util.Arrays;


public class MergeSort {

    public static void main(String[] args) throws IOException{
        BufferedReader R = new BufferedReader(new InputStreamReader(System.in));
        int arraySize = Integer.parseInt(R.readLine());
        int[] inputArray = new int[arraySize];
        for (int i = 0; i < arraySize; i++) {
            inputArray[i] = Integer.parseInt(R.readLine());
        }
        mergeSort(inputArray);

        for (int j = 0; j < inputArray.length; j++) {
            System.out.println(inputArray[j]);
        }

    }

    static void mergeSort(int[] A) {
        if (A.length > 1) {
            int q = A.length/2;
            int[] leftArray = Arrays.copyOfRange(A, 0, q);
            int[] rightArray = Arrays.copyOfRange(A,q+1,A.length);
            mergeSort(leftArray);
            mergeSort(rightArray);
            A = merge(leftArray,rightArray);
        }
    }

    static int[] merge(int[] l, int[] r) {
        int totElem = l.length + r.length;
        int[] a = new int[totElem];
        int i,li,ri;
        i = li = ri = 0;
        while ( i < totElem) {
            if ((li < l.length) && (ri<r.length)) {
                if (l[li] < r[ri]) {
                    a[i] = l[li];
                    i++;
                    li++;
                }
                else {
                    a[i] = r[ri];
                    i++;
                    ri++;
                }
            }
            else {
                if (li >= l.length) {
                    while (ri < r.length) {
                        a[i] = r[ri];
                        i++;
                        ri++;
                    }
                }
                if (ri >= r.length) {
                    while (li < l.length) {
                        a[i] = l[li];
                        li++;
                        i++;
                    }
                }
            }
        }
        return a;

    }

}

解决方案

Here is a corrected version of your code:

import java.io.*;
import java.util.Arrays;


public class MergeSort {

    public static void main(String[] args) throws IOException{
        BufferedReader R = new BufferedReader(new InputStreamReader(System.in));
        int arraySize = Integer.parseInt(R.readLine());
        int[] inputArray = new int[arraySize];
        for (int i = 0; i < arraySize; i++) {
            inputArray[i] = Integer.parseInt(R.readLine());
        }
        mergeSort(inputArray);

        for (int j = 0; j < inputArray.length; j++) {
            System.out.println(inputArray[j]);
        }

    }

    static void mergeSort(int[] A) {
        if (A.length > 1) {
            int q = A.length/2;

            int[] leftArray = Arrays.copyOfRange(A, 0, q);
            int[] rightArray = Arrays.copyOfRange(A,q,A.length);

            mergeSort(leftArray);
            mergeSort(rightArray);

            merge(A,leftArray,rightArray);
        }
    }

    static void merge(int[] a, int[] l, int[] r) {
        int totElem = l.length + r.length;
        //int[] a = new int[totElem];
        int i,li,ri;
        i = li = ri = 0;
        while ( i < totElem) {
            if ((li < l.length) && (ri<r.length)) {
                if (l[li] < r[ri]) {
                    a[i] = l[li];
                    i++;
                    li++;
                }
                else {
                    a[i] = r[ri];
                    i++;
                    ri++;
                }
            }
            else {
                if (li >= l.length) {
                    while (ri < r.length) {
                        a[i] = r[ri];
                        i++;
                        ri++;
                    }
                }
                if (ri >= r.length) {
                    while (li < l.length) {
                        a[i] = l[li];
                        li++;
                        i++;
                    }
                }
            }
        }
        //return a;

    }

}

 
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