自定义数组java

自定义数组

package com.lexie.arr;

public class MyArray {
	private long[] arr;
	// 表示有效数据的长度
	private int elements;

	public MyArray() {
		arr = new long[50];
	}

	public MyArray(int maxsize) {
		arr = new long[maxsize];
	}

	public void insert(long value) {
		arr[elements] = value;
		elements++;
	}

	public void display() {
		System.out.print("{");
		for (int i = 0; i < elements; i++) {
			System.out.print(arr[i] + " ");
		}
		System.out.println("}");
	}

	public int search(long value) {
		int i;
		for (i = 0; i < elements; i++) {
			if (value == arr[i]) {
				break;
			}
		}
		if (i == elements) {
			return -1;
		} else {
			return i;
		}
	}

	public long get(int index) {
		if (index >= elements || index < 0) {
			throw new ArrayIndexOutOfBoundsException();
		} else {
			return arr[index];
		}
	}

	public void delete(int index) {
		if (index >= elements || index < 0) {
			throw new ArrayIndexOutOfBoundsException();
		} else {
			for (int i = index; i < elements; i++) {
				arr[index] = arr[index + 1];
			}
			elements--;
		}
	}

	public void changge(int index, int newvalue) {
		if (index >= elements || index < 0) {
			throw new ArrayIndexOutOfBoundsException();
		} else {
			arr[index] = newvalue;
		}
	}
}

更改为有序数组

public void insert(long value) {
		int i;
		for (i = 0; i < elements; i++) {
			if (arr[i] > value) {
				break;
			}
		}

		for (int j = elements; j > i; j--) {
			arr[j] = arr[j - 1];
		}
		arr[i] = value;
		elements++;
	}

二分法

public int binarySearch(long value) {
		int middle = 0;
		int low = 0;
		int pow = elements;

		while (true) {
			middle = (pow + low) / 2;
			if (arr[middle] == value) {
				return middle;
			} else if (low > pow) {
				return -1;
			} else {
				if (arr[middle] > value) {
					pow = middle - 1;
				} else {
					low = middle + 1;
				}
			}

		}
	}

测试

package com.lexie.arr;

public class TestArray {
	public static void main(String[] args) {
		MyArray arr =new MyArray();
		arr.insert(13);
		arr.insert(34);
		arr.insert(90);
		
		
		arr.display();
		System.out.println(arr.search(90));
		
		System.out.println(arr.get(1));
		
		arr.delete(2);
		arr.display();
		
		arr.changge(0, 12);
		arr.display();
		
		System.out.println("有序数组测试----------------------");
	
		MyOrderArray order = new MyOrderArray();
		order.insert(90);
		order.insert(30);
		order.insert(80);
		order.insert(10);
		order.display();
		
		System.out.println(order.binarySearch(90));
	
	}
}