有序数组的增删改查

女爷i 2024-03-26 19:03 43阅读 0赞

public class ArrDemo {
         private int[] arr = new int[20];
         private int flag = 0;
    
         public void add(int x){
              System.out.print("插入的新数据:" +x+" ");
              if(flag==arr.length){
                   int[]  arrNew = new int[arr.length*2];
                   for (int i = 0;i< arrNew.length;i++){
                        arrNew[i]=arr[i];
                   }
                   arr=arrNew;
              }
              //找到插入的正确位置
              if(flag==0){
                   arr[0]=x;
                   flag++;
                   return;
              }
              int insertIndex=getInsertIndex(x);
              for(int i = flag;i>insertIndex;i--){
                   arr[i] = arr[i-1];
              }
              flag++;
              arr[insertIndex]=x;
         }
    
    
         public int getIndex(int x){
              int left = 0;
              int right = arr.length-1;
              while (left<=right){
                   int middle = (left+right)/2;
                   if (arr[middle]==x){
                        return middle;
                   }else if(arr[middle]<x){
                        left=middle+1;
                   }else {
                        right=middle-1;
                   }
              }
              return -1;
         }
    
         //有序数组要插入的位置
         public int getInsertIndex(int x){
              int left = 0;
              int right = flag-1;
              while (left <= right){
                   int middle = (left+right)/2;
                   if (arr[middle]==x){
                        return middle;
                   }else if(arr[middle]<x){
                        left=middle+1;
                   }else {
                        right=middle-1;
                   }
              }
              int middles = (left+right)/2;  //防止右侧越界
              if(arr[middles] >= x){
                   return middles;
              }else{
                   return middles+1;
              }
         }
    
         public void change(int oldNum,int newNum){
              int index = getIndex(oldNum);
              arr[index]=newNum;
         }
    
         public void del(int x){
              int index = getIndex(x);
              for (int i =index;i<flag-1;i++){
                   arr[i]=arr[i+1];
              }
              flag--;
         }
    
         public void show(){
              for (int i =0;i<flag;i++){
                   System.out.print("arr["+i+"]:"+arr[i]+" ");
              }
         }

测试：

public class ArrTest {
        public static void main(String[] args) {
            ArrDemo arrDemo = new ArrDemo();
           arrDemo.add(1);arrDemo.add(8);arrDemo.add(9999);arrDemo.add(12);
            arrDemo.add(5);arrDemo.add(55);arrDemo.add(-14);arrDemo.add(666);
            System.out.println("--------------------------------");
            arrDemo.show();
        }
    }

![d4859a67ce3d4904a1532207b348cabf.png][]

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今日状态不佳，字少谅解！![f13df843377f48da807d37b66327d838.jpeg][]

[d4859a67ce3d4904a1532207b348cabf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/6dba483c3c1849aea7fc44d7d780a80c.png
[f13df843377f48da807d37b66327d838.jpeg]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/26/3f6a76b9bdb5460aa82ad6711fbb53d2.png