java 算法

java 算法

1、递归的方法实现冒泡

1 public class SortTest {
 2      public static void main(String[] args) {
 3          int[] arr={12,5,16,3,9,0,158,214,85};
 4          queue(arr);
 5          System.out.println(Arrays.toString(arr));
 6 ｝
 7  public static int[] queue(int[] a) {             9          for(int j=a.length-1;j>0;j--){
10                   if(a[j]<a[j-1]){
11                           int t=a[j];
12                           a[j]=a[j-1];
13                           a[j-1]=t;
14                   return queue(a);
15            }     
16         }18         return a;
19     }
20   }
21 ｝

 2、两个有序数组合并为一个有序数组

package com.itheima.suanfa;

public class _01TwoArrayOneArray01 {
    public static void main(String[] args) {
        //定义两个数组下标，遍历并记录index使用；
        int indexM =0;
        int indexN =0;
        int k=0;
        int[] arrayM = new int[]{1,4,6,7,8};
        int[] arrayN = new int[]{2,3,5,9,11};
        int[] res = new int[arrayM.length+arrayN.length];
        while (indexM<arrayM.length && indexN<arrayN.length){
            if(arrayM[indexM]<arrayN[indexN]){
                res[k]=arrayM[indexM];
                indexM++;
            }
            else{
                res[k]=arrayN[indexN];
                indexN++;
            }
            k++;
        }
        if(indexM!=arrayM.length){
            for(int i=indexM;i<arrayM.length;i++){
                res[k]=arrayM[i];
                k++;
            }
        }
        else{
            for(int i=indexN;i<arrayN.length;i++){
                res[k]=arrayN[i];
                k++;
            }
        }
        for(int a =0;a<k;a++){
            System.out.println(res[a]);
        }

    }
}

 3、单向链表反转

package com.itheima.suanfa;

public class _02SingleLinkReverse {
    public static void main(String[] args) {
        DataNode dataNode = new DataNode(1);
        DataNode dataNode1 = new DataNode(2);
        dataNode.setNext(dataNode1);
        DataNode dataNode2 = new DataNode(3);
        dataNode1.setNext(dataNode2);

        printLinkData(dataNode);

        DataNode nodeNew=reverse1(dataNode);

        printLinkData(nodeNew);
    }

    /**
     * 遍历实现 通用实现方法
     *
     * @param head
     * @return
     */
    public static DataNode reverse1(DataNode head) {
        if (null == head || null == head.getNext())
            return head;
        DataNode pre=null;
        DataNode cur=head;
        DataNode next=null;
        while (cur!=null){
            next=cur.getNext();
            cur.setNext(pre);
            pre=cur;
            cur=next;
        }
        return pre;
    }

    public static void printLinkData(DataNode node){
        System.out.println(node.getData());
        if (node.getNext()!=null){
            printLinkData(node.getNext());
        }

    }
}
class DataNode {

    private int data;
    private DataNode next;
    public int getData() {
        return data;
    }
    public void setData(int data) {
        this.data = data;
    }
    public DataNode getNext() {
        return next;
    }
    public void setNext(DataNode next) {
        this.next = next;
    }
    public DataNode(int data) {
        this.data = data;
    }
}